Clark GEX20-30 (RATED CAPACITY : 2000~3000kg). SERVICE MANUAL (2006)

Group 30, Hydraulic Control Valve/Lift Circuit

Hydraulic Control Valve Replacement

Control Valve Linkage Reassembly

1. Insert the clevis pins through the rod-end clevises

Valve Replacement

and valve spools of the lift and tilt spools (and auxil-

iary-lever rods and spools where applicable) and

1. Install the main valve on the valve mounting bracket.

secure with the cotter rings. Rotation of the valve

2. Install the valve mounting bracket on the frame.

spools is required to allow insertion of the clevis

pins. Rotate spools back so all pins are in line.

Torque to

3. Install the hydraulic lines on the proper ports. Make

Clevis Pin

sure all lines are clean, arerouted correctly in the

truck, and are not kinked. Torque fittings according

Cotter Pin

to “Hydraulic Fitting Tightening Procedure” in

Valve Spool

Group 40.

NOTE

Tilt Cylinder

The illustration above and system specifica-

Lines

tion torques also apply for auxiliary hydrau-

lic functions, such as a side-shifter or rotator.

2. Set the interval of lever, then tighten the nuts under

To Upringt

the lever with torque of 40-50Nm(30-33ft.lb).

Feed Line

Return Line

from Pump

to Sump

SM 765, Sep ’06

Hydraulic Control Valve Removal and Replacement • 30-5-3

Group 30, Hydraulic Control Valve/Lift Circuit

Reinstall Valve

Operational Checks

1. Reinstall valve and valve plumbing.

1. Operate the truck and hydraulic system. Check the

system for leaks.

Torque to

WARNING

Do not use your hands to check for hydraulic

leakage. Use a piece of cardboard or paper to

search for leaks. Escaping fluid under pres-

sure can penetrate the skin causing serious

injury. Relieve pressure before disconnecting

hydraulic or other lines. Tighten all connec-

tions before applying pressure. Keep hands

and body away from pinholes and nozzles

which eject fluids under high pressure.

If any fluid is injected into the skin, it must

be surgically removed within a few hours by

Torque to

a doctor familiar with this type injury or

gangrene may result.

2. Check the operation of the valve and hydraulic sys-

Lift and Tilt Pump Switches

tem by moving the valve control levers to the various

positions. The levers must operate smoothly with no

binding. When released from any working position,

Adjustment

the levers must return sharply to their neutral posi-

tions.

1. Turn key switch to the OFF position.

If valve spools do not moved or return to correct

2. Loosen switch mounting screws.

position for full function of lift, tilt, or auxiliary cyl-

inders:

3. Adjust switch to activate after 2 mm (0.08 in.) of

spool travel from neutral.

a. When inserting the pin to the lever, check it is

smoothly inserted.

4. Tighten mounting screws.

Micro Switch

Switch shown

Switch Mounting

mounted

Bracket

Clevis Pin

Cotter Pin

Valve Spool

3. Refer to Section 4, “Hydraulic System Pressure-

Check” if valve was disassembled or overhauled.

30-5-4 • Hydraulic Control Valve Removal and Replacement

SM 765, Sep ’06

Group 32, Tilt Cylinders

Section 1

Tilt Cylinder Specifications and Description

Specifications

Service Intervals

See Group 30 for hydraulic system specifications.

Tilt Cylinder Drift Test: Every 50-250 hours or each PM.

Tilt Cylinder Type: Double-acting

Tilt Cylinder Check and Adjustment: Every 50-250 hours

or each PM.

Maximum Operating Pressure: 21,000 kPa (3,000 psi)

Tilt Cylinder Rod Seal Condition Check: Every 50-250

Tilt Ranges*:

hours or each PM.

MAST

BACK

FORWARD

MFH mm(in)

Tilt Cylinder Mounting Check and Tightening: Every 50-

TYPE

"B"( ˚ )

"F"( ˚ )

250 hours or each PM.

GEX

Tilt Cylinder Rod-End Check and Tightening: Every 50-

STD

~2015(83)

250 hours or each PM.

STD

2680(105.5)~3860(152)

STD

4165(164)~4620(182)

Tilt Cylinder Rod-End Lubrication: Every 50-250 hours

STD

5170(203.5)

or each PM.

TSU

3860(152)~4800(189)

TSU

5050(199)~6100(240)

Description

TSU

6370(251)~

The tilt cylinders provide backward and forward tilt of the

QUAD

ALL

upright. The forward and back tilt angles are governed by

the cylinder stroke and by use of spacers and different

Abbreviations: Std = Standard, high-visibility upright;

length rod ends. The tilt cylinders are pin-mounted to the

TSU = Triple-stage upright; MFH = maximum fork

truck frame and upright using yokes, clevises, and pins.

height; B = back tilt; F = forward tilt. See truck data plate

Pins are held in place by a lock plate and fastener to pre-

for upright MFH.

vent the pins from working their way out.

The tilt cylinders are serviced by removing them from the

Fastener Torques

truck and disassembling them for complete overhaul,

including installation of new seals and or other cylinder

Rod-End Yoke Bolts: 166-193 N.m (122-142 ft-lb)

components.

Rod-End Pin Lock Plate Fasteners: 40-45 N⋅m (30-33 ft-

The tilt lock valve is integrated into the tilt section of the

lb).

main hydraulic control valve. The tilt lock valve prevents

Base Mount Pin Lock Plate Fasteners: 40-45 N⋅m (30-33

the upright from tilting forward when the truck is not run-

ft-lb).

ning. The tilt lock valve is not serviceable and must be

replaced as a valve section if defective.

SM 765, Nov ’06

Tilt Cylinder Specifications and Description • 32-1-1

Group 32, Tilt Cylinders

Section 2

Tilt Cylinder Checks and Adjustments

Tilt Cylinder Drift Test

Drift Causes and Remedies

Tilt Cylinder Racking Check

Forward Adjustment

Backward Adjustment

Tilt Flow Control Adjustments

3. Raise the capacity load 2500 mm (98.5 in) off the

! CAUTION

ground and tilt the upright vertical. Shut off the truck.

SAFE PARKING. Before working on truck:

1. Park truck on a hard, level, and solid

surface, such as a concrete floor with no

gaps or breaks.

2. Put upright in vertical position and fully

lower the forks or attachment.

3. Put all controls in neutral. Turn key

switch OFF and remove key.

4. Apply the parking brake and block the

wheels.

Tilt Cylinder Drift Check

To check tilt cylinder drift, a rated capacity load is placed

on the forks, lifted up and held to determine if the tilt cyl-

inder rods moves (drifts) in a specified length of time.

It is recommended that a test load, made up of a full-

capacity load equally distributed on a 1220 x 1220 mm

(48 x 48 in) pallet, be used. The material used to make up

the test load must be stacked to provide load stability and

must not extend beyond the pallet. It must be secured on

the pallet. Refer to the truck data plate for capacity rating.

4. Measure and write down the distance between the

1. Adjust fork width as wide as possible to distribute

cylinder-spacer face and the rod-end yoke.

the load. Refer to truck nameplate for capacity rating.

Measure rod

! CAUTION

distance here

Test load must be stacked stably, not extend

beyond the pallet, and be secured on the pal-

let. Clamp the load on the load backrest or

fork bar to avoid sliping out from fork.

2. Drive the forks into the load pallet until the test load

and pallet rest against the load backrest. Apply the

parking brake and chock the wheels.

SM 765, Nov ’06

Tilt Cylinder Checks and Adjustments • 32-2-1

Group 32, Tilt Cylinders

5. Wait five minutes and measure and write down dis-

tance between rod end and spacer.

6. The measurement must not exceed the following

measures:

Temperature

Drift

0.5°, 3.9mm @ 1 min

50°C(122°F)

5°, 39 mm @ 10 min

Drift Causes and Remedies

Tilt cylinder drift indicates the following possible prob-

lems:

• Tilt cylinder hydraulic circuit hoses or fittings are

leaking. Check the circuit components and repair

as necessary.

Forward Adjustment

• Cylinder piston seals are worn, damaged, or defec-

tive allowing fluid past the piston and causing the

1. Slowly tilt upright fully forward to the end of the tilt

rod to drift. Consider rebuilding the cylinders if the

cylinder stroke.

other remedies in this list are not successful. See

2. As the cylinders approach the end of the stroke,

Section 3 for cylinder removal and replacement

watch both piston rods for equal movement and

and Section 4 for cylinder repair, if necessary.

upright for twisting. Note if upright “racks” (is

• The main hydraulic tilt valve is misadjusted, worn,

twisted at the end of its movement by unequal stroke

or defective. Fluid is leaking past the valve and

of tilt cylinders).

causing the tilt cylinders to drift. See Group 30 for

NOTE

hydraulic valve troubleshooting.

Correct the twisting effect by shortening the

cylinder that is the longest length. Forward

Tilt Cylinder Racking Check

twisting must be adjusted before backward

Upright racking occurs when tilt cylinder strokes are

twisting. If forward adjustment is not

unequal. Cylinders should be checked regularly during

needed, continue with backward adjustment.

operation to determine if cylinder strokes are the same. To

check for racking:

3. To adjust, loosen rod-end yoke capscrew on the tilt

cylinder that extends the farthest, and turn piston rod

• Make sure uuck is parked on level surface with

parking brake applied and wheels chocked.

into rod-end yoke to shorten.

• Check condition of the tilt cylinder, rod-end yoke,

Loosen

mounting pins, piston rod, rod wiper, cylinder

capscrew.

gland, etc., for excessive wear or damage. Make

repairs before making twisting adjustment.

Turn to adjust.

• Use a capacity load (see truck nameplate) centered

on the forks.

! CAUTION

Be sure to secure the load to the fork carriage

to keep it from falling off when tilted for-

ward.

Raise the upright only to the height that will

allow the fork tips to clear the floor when

Forward Adjustment: Pneumatic-tire truck rod-end yoke

tilted fully forward.

orientation shown.

32-2-2 • Tilt Cylinder Checks and Adjustments

SM 765, Nov ’06

Group 32, Tilt Cylinders

NOTE

4. Use rod shims to fill in the space between the rod-

Use wrench flat on rod under spacer (if

end yoke and spacer. Screw rod back into yoke the

installed). Move spacer for access.

same number of turns needed to remove.

4. Continue to turn rod into rod end until tilt cylinder

strokes are equal.

Rod Shim

Rod-End

IMPORTANT

Yoke

Cylinder Rod

The rod must he threaded onto the rod-end

yoke a distance at least as great as the diame-

Wrench Flat

ter of the rod plus 6.5 mm (0.25 in).

Add 6.5

Spacer

mm (.25

in) to

diameter

of rod.

5. Tighten capscrew of the rod-end yoke to 166-193

Thread rod into rod-

end yoke the rod

N⋅m (122-142 ft-lb), and repeat the racking test.

diameter plus 6.5 mm

6. Repeat steps l-5 for fine corrections if any racking

(0.25in).

remains evident.

7. When no racking occurs, retighten yoke capscrew to

5. Tighten capscrew of the rod-end yoke to 166- 193

166-193 N⋅m (122-142 ft-lb).

N.m (122-142 ft-lb), and repeat the racking test.

8. Check all tilt functions before returning the truck to

6. Repeat steps 1-5 for fine corrections if any racking

service.

remains evident.

7. When no racking occurs, retighten capscrew of the

rod-end yoke to 166-193 N⋅m (122-142 Et-lb).

8. Check all tilt functions before returning the truck to

service.

Backward Adjustment

Perform forward check and adjustment first. Then:

1. Slowly tilt upright fully backwards while watching

piston rods. They should both bottom out at the same

time. If they don’t, adjust backward tilt using the fol-

lowing steps.

2. Stop the upright when the first tilt cylinder bottoms

out against its rod spacer.

3. Go to the opposite cylinder and remove the capscrew

on the rod-end yoke and screw rod out of yoke.

Count the number of turns required to remove the rod

from the yoke.

SM 765, Nov ’06

Tilt Cylinder Checks and Adjustments • 32-2-3

Group 32, Tilt Cylinders

! CAUTION

WARNING

SAFE PARKING. Before working on truck:

The upright assembly is heavy. Use only

hoists with enough capacity to lift the entire

1. Park truck on a hard, level,-and solid

assembly. Keep hands and feet away from the

surface, such as a concrete floor with no

assembly. Use prybars to move the assembly

gaps or breaks.

into position for tilt cylinder replacement.

2. Put upright in vertical position and fully

lower the forks or attachment.

3. Remove the floorboard.

3. Put all controls in neutral. Turn key

4. Put a drain pan under the truck at each tilt cylinder

switch OFF and remove key.

position before removing the hydraulic lines. Discon-

nect and cap hydraulic lines from the tilt cylinders

4. Apply the parking brake and block the

(see illustration on facing page). Remove the hose

wheels.

connections on both sides of the tee fittings of theri-

ghtside cylinder. Keep all fittings and ports clean.

Tilt Cylinder Removal

1. Move tilt lever back and forth several times to relieve

any pressure.

2. Use an adequate chain and hoist to support the

upright so that it cannot fall when tilt cylinder pins

are removed.

Bearing

Rod-End Yoke

Base Pin

Mounting Bolt

Grease Fitting

Base Pin

Tilt Cylinder Mounting Components

5. Support cylinder with a sling to prevent the cylinder

from dropping when pins are removed.

32-3-2 • Tilt Cylinder Removal and Replacement

SM 765, Nov ’06

Group 32, Tilt Cylinders

6. Remove lock-plate from tilt cylinder rod-end yoke.

Tilt Cylinder Replacement

Use a soft drift and hammer to tap rod-end pin out of

yoke.

1. Position tilt cylinder base yoke on frame mounting

bracket.

7. Pop the cover from tilt cylinder base access port on

the step to the operator’s compartment.

2. Insert base pin in cylinder base yoke and through

frame mounting bracket, making sure slot in pin is in

8. Remove the lock-plate from cylinder base yoke. Use

line with the lock-plate. Grease fitting must point

a soft drift and hammer to tap pin out of yoke.

toward center of truck.

9. Remove cylinder assembly.

IMPORTANT

Make sure the spherical bearing is aligned so

Parts Inspection

that pin fits smoothly in yoke.

1. Clean all bearings, pins, and other components in an

3. Install base pin lock-plate in slot and fasten to yoke

approved cleaning fluid.

with fastener. Tighten fastener to a torque of 40-45

2. Inspect all parts for scratches, nicks, dents, and wear.

N⋅m (30-33 ft-lb).

Check the cylinder rods to be sure they are smooth

4. Position rod-end yoke on upright mounting bracket

with no scratches. Check all threaded parts for dam-

and insert rod-end pin, making sure lock-plate slot is

age.

in correct position. Grease fitting must be toward

3. Replace all parts which show damage.

center of truck. Make sure the spherical bearing is

aligned so that pin fits smoothly in yoke.

4. If parts are to be left exposed, coat all mating sur-

faces of parts with a light layer of engine oil.

Tee Fitting

Till Cylinder Hydraulic Fittings

SM 765, Nov ’06

Tilt Cylinder Removal and Replacement • 32-3-3

Group 32, Tilt Cylinders

NOTE

6. Install tilt cylinder hydraulic lines. Check Group 40

If the rod-end yoke has been removed from

for hydraulic fitting tightening procedures. O-rings

the rod or loosened for adjustment, reinstall

of fittings should be lightly coated with clean

the clamp bolts to a torque of 166-193 N.m

hydraulic fluid or compatible oil.

(122-142 ft-lb). Nuts must be on inside of

7. Remove hoist chain from upright.

upright rails Orientation of the rod-end yoke

bolt hole is to be up as shown on the left side

8. See Section 2 for tilt cylinder adjustment procedures.

of the illustration on the previous page.

When adjustments are made, check all upright com-

ponents under load before returning the truck to ser-

5. Install rod-end lock-plate in slot and fasten to yoke

vice. Nuts must be on inside.

with fastener and washer. Tighten fastener to a torque

of 40-45 N⋅m (30-33 ft-lb).

32-3-4 • Tilt Cylinder Removal and Replacement

SM 765, Nov ’06

Group 32, Tilt Cylinders

2. Carefully pull the rod, piston assembly, and gland

Preparation For Disassembly

from the cylinder barrel. Remove gland from rod.

IMPORTANT

Overhaul tilt cylinders only in a clean, dust-

WARNING

free location, using clean tools and equip-

The use of compressed air to blow the piston

ment. Dirt or grit will damage the highly-

out of the barrel is not recommended. High-

machined surfaces and will result in leakage

pressure air can result in piston and rod

or premature failure of components. Cleanli-

being ejected at high velocity (explosively),

ness of the hydraulic circuit is extremely

causing severe injury to personnel and prop-

important to the proper operation and main-

erty damage.

tenance of the system. Be sure the work area

is clean.

3. Remove and discard the piston packing and wear

rings from the piston.

1. Before disassembly, the exterior of the tilt cylinder

should be carefully cleaned to remove all dirt and

Piston Seal

Wear Ring

grease accumulation.

2. Be sure all hydraulic oil has been removed from the

cylinder. Stroking the piston rod will help force the

oil out.

3. Before starting disassembly, the tilt cylinder should

be carefully examined to determine if there is any

evidence of external damage.

4. Remove and discard the rod U-cup seal, O-ring, and

Disassembly

piston rod wiper from the gland.

The tilt cylinder can be held by clamping the base end or

the barrel in a vise while disassembling.

O-Ring + Backup Ring

O-Ring

IMPORTANT

DU Bush

Rod Wiper

Do not use excessive force when clamping on

Dust Wiper

the barrel.

1. Remove the gland with a hook wrench. Carefully

pull the gland assembly from the cylinder tube and

slide it off the cylinder rod.

O-Ring

32-4-2 • Tilt Cylinder Overhaul

SM 765, Nov ’06

Group 32, Tilt Cylinders

Replace the piston packing and wearing.

Inspection

1. Carefully clean all parts in an approved solvent and

Piston Seal

Wear Ring

place on a clean surface.

2. Check the piston and rod for damage. Look for

gouges, scratches, corrosion, or evidence of unusual

wear. Minor surface damage may be repaired by use

of fine abrasion cloth or stoning. Deeper damage will

require replacement of piston rod assembly.

3. Be sure the threads on rod are undamaged.

4. Inspect the tilt cylinder barrel internal bore for wear,

Install gland on piston rod. Use gentle pressure and

scratches or other damage. Check the outside for

careful movements to avoid damage to the U-cup

damage. Inspect all welds for cracks.

seal and rod wiper when these parts are moved over

Deep gouges or pitted surfaces require replacement

the piston rod end.

of parts.

NOTE

Check the gland, base end, and ports for cracks or

damage that could cause failure. Inspect the ports to

Reassemble cylinder carefully to prevent

be sure they are free of contamination and that the

damage to seal lips and O-rings.

threads are clean and not damaged.

Install piston into cylinder barrel. Be careful not to

5. Put a light coating of hydraulic fluid on all parts. If

damage the piston seals when installing the piston

parts are to be left disassembled for a period of time,

into end of cylinder.

e.g., overnight, they should be covered with a clean

cloth.

Install gland into cylinder them screw the gland into

the cylinder barrel with a hook wrench. When tight-

ing, do not damage the seal. Tighten torque : 60±6

Reassembly

kgf⋅m

Be sure inside of cylinder and all parts are clean before

starting reassembly. Seals may be lubricated with hydrau-

O-Ring

lic oil to assist assembly into cylinder barrel.

1. Install piston dust wiper, rod seal, and O-ring on the

gland. Make sure rod seal and dust wiper are

installed in proper orientation as shown in the illus-

tration.

O-Ring + Backup Ring

O-Ring

DU Bush

Rod Wiper

Dust Wiper

Check the assembly by making sure the piston slides

freely in and out of the cylinder.

See Section 3 for replacement procedures ; see Section 2

for checks and adjustments before returning the truck to

service.

SM 765, Nov ’06

Tilt Cylinder Overhaul • 32-4-3

Group 34, Uprights

Section 1

Upright Specifications and Description

General Specifications

Upright

Upright Weight: (Approximately 359 kg (792 lb) to

Upright Type Number Cylinder Type

approximately 993 kg (2190 lb) without carriage.

<GEX20-30>

Carriage Weight: Approximately 89 kg (196 lb) to 99 kg

STD Pneu

V2324

Piston-Type Lift Cylinder

(220 lb) with a 41 inch carriage.

TSU Pneu

M2324

Piston-Type Secondary Cylin-

der

Fork Weight: Approximately 44 to 99 kg each (97 to 220

Hi-Lo Pneu H2317

Ram-Type Secondary

lbs).

Cylinder

IMPORTANT

Before hoisting, the weights of upright, car-

Drift:

riage, forks and attachments being lifted

With the upright substantially vertical the descent of the

must be combined to determine what lifting

rated load caused by an internal leakage in the hydraulic

capacity is required of the hoisting equip-

system shall not exceed 100mm (4in) during the first

ment.

10min with the oil in the hydraulic system at normal oper-

ating temperature. If drift over 100 mm (4 in) in ten min-

Capacities and Lift Heights: Upright, carriage, and fork

utes is evident, cylinder should be checked for internal

capacity and upright lift heights are listed on the truck’s

leakage. See Section 3 for drift test procedures.

data plate.

Lubricants:

Fastener and Fitting Torque Specifications

• All Purpose Grease (MS-9)

Pin Mounting Bolts: 280~320 N⋅m (205~234 ft-lb)

• Innerslide Lubricant (Clark P/N 886396)

Load Back Rest: 215-264 N⋅m (159-195 ft-lb)

• Chain and Cable Lube (Clark P/N 886399)

Chain Anchor Bolt Jam Nut: 100-200 N⋅m (74-148 ft-lb)

Carriage Side-Thrust Roller Bolts(External): 40-50 N⋅m

Cylinder Types

(29.5-37 ft-lb)

Standard uprights use two lift cylinders. Triple stage and

Carriage Side-Thrust Roller Bolts(Internal): 70-80 N⋅m

Hi-Lo uprights use three cylinders, a primary (center-

(52-59 ft-lb)

mounted) cylinder, and two secondary cylinders. All pri-

Hose Fittings: See Group 40, “Hydraulic Fitting Tighten-

mary cylinders used on triple-stage uprights (TSUs & Hi-

ing Procedure.”

Lo) are piston cylinders. The lift and secondary cylinders

used on standard, Hi-Lo uprights and TSUs can be piston

Rod End Bolts: 170-190 N⋅m (125-140 ft-lb)

cylinders.

Tilt Cylinder Rod-End Pin Lock Plate: 40-45 N⋅m (30-33

ft-lb).

The types of cylinders used on the truck are listed below.

Check the first five characters of the upright number

stamped on the upright of the truck to determine the type

Service Intervals

of cylinder, piston used on the upright.

• All upright components should be visually checked

every day during the Operator’s Daily Inspection.

IMPORTANT

• A thorough visual inspection should be performed

Before removing any component for over-

by a trained service professional every 50-250

haul, make sure the correct repair parts,

hours.

seals, and gasket sets are available.

• Lift chains should be inspected and lubricated

every 50-250 hours or monthly.

SM 765, Nov ’06

Upright Specifications and Description • 34-1-1

Group 34, Uprights

• Lift chain tension should be checked every 50-250

Piston-type cylinders contain a by-pass check valve in the

hours or monthly.

piston that allows air and fluid that have accumulated in

• Upright and carriage roller checks should be per-

the rod end of the cylinder to return to the system. The

formed every 50-250 hours or monthly.

check valve can be removed and cleaned if indicated by

troubleshooting. A non-serviceable check-ball-type cush-

• Roller patterns should be checked every 6 months

ioning function is built into ram and piston cylinders for

or after 1000 hours of service.

smooth staging during the lowering cycle. The primary

• Racking and drift tests should be performed every

cylinder on TSUs incorporates cushioning on the lift

50~250 hours or monthly.

cycle. A velocity fuse in the hydraulic port of the lift cyl-

• The complete extended inspection should be per-

inders (secondary cylinders on TSUs) prevents the mast

formed at least every year or 2000 hours of opera-

from falling rapidly in case of sudden fluid pressure loss

tion.

due to line breaks or other malfunction of the hydraulic

circuit.

Description

As the cushion system is added to lift cylinder of standard

The upright assembly includes the lift chains, lift cylin-

upright and the 1st cylinder of TSU, the speed will get

ders, carriage, forks, and mast or rail sets. Each of the

slow for a moment before the fork touches the ground. It

components can be serviced using the tests, checks,

is helpful to protect the ground.

adjustments, and removal and replacement procedures in

the following Sections.

As explained in more detail in Group 30, the main pump

sends fluid to the main hydraulic control valve, which

The upright uses the hydraulic cylinders and chain sets to

contains spools that route fluid to the lift cylinders and tilt

lift the carriage and rail sets. On standard, two-stage

cylinders. The valve assembly also contains a counter-

uprights, the lift cylinders lift the carriage with chains and

balance valve that prevents upright tilt when the truck is

directly lift the inner rail set. On triple-stage uprights, the

not operating.

primary (free-lift) cylinder lifts the carriage by chains.

When the primary cylinder reaches its maximum exten-

Fluid flow rates for lift functions are factory set and not

sion, fluid is diverted to the secondary lift cylinders,

adjustable. Flow rates for tilt and auxiliary functions are

which lift the inner rails using a second set of chains and

controlled by adjustments on the main hydraulic valve. A

lift the intermediate rails by direct lift.

non-adjustable “load-lowering” flow valve mounted on

the upright limits upright lowering speed.

On Hi-Lo uprights, the primary(free-lift) cylinder lifts the

carriage by chanis. The secondary cylinders directly lift

Groups 29 and 30 contain general hydraulic information

the inner rail set by rod. Hi-Lo uprights not used second

including upright hydraulic functions. Other hydraulic

set of chain for secondary cyliner.

checks for the upright appear in “Troubleshooting,” Sec-

tion 2.

Friction and play between the nesting rails is controlled by

roller sets mounted on the rails and carriage. When rails or

rollers become worn, the gap between the rollers and rails

becomes larger, creating more play in lifting and lowering

operations. The rail web to roller side clearances can be

reduced by shimming the rollers to close the gap between

the roller and rails. The gap between the rail flange and

roller bearing surface can be reduced by the use of over-

size rollers on a one-time basis.

Forks use a hanger design for mounting on the carriage.

Auxiliary attachments may be added to the upright for

specialized handling operations. The hydraulic circuit is

modified with a hose adapter kit and an auxiliary section

is added to the main hydraulic valve to operate the attach-

ment.

The lift and secondary cylinders on standard uprights and

triple-stage uprights (TSUs) are piston type cylinders. The

primary cylinder on TSUs and HILO are piston-type cyl-

inder. See the chart under “Specifications” to determine

the type of cylinder used on the upright you are servicing.

34-1-2 • Upright Specifications and Description

SM 765, Nov ’06

Group 34, Uprights

Upper Roller

*Assembly of slider and adjustment of shim:

Assemble the slider as the backside of rail and the

friction surface of slider are in parallel.

Match the outer rail end and inner rail end, and then

make the gap between the flange face of inner rail

and the slider will be within 0.5mm.

Chain Sheave

Lift Cylinder

Chain Anchor

Outer Rail Set

Lift Chain

Load Lowering

Inner Rail Set

Flow Valve

Typical Standard Upright Assembly

Upper Roller

*Assembly of slider and adjustment of shim:

Lower Roller

Assemble the slider as the backside of rail and the

friction surface of slider are in parallel.

Match the outer rail end and inter rail end, and then

make the gap between the flange face of inter rail

and the slider will be within 0.5mm.

Chain Sheave

Chain Anchor

*Assembly of slider and adjustment of shim:

Assemble the slider as the backside of rail and the

friction surface of slider are in parallel.

Match the Inter rail end and inner rail end, and then

make the gap between the flange face of inner rail

Secondary

and the slider will be within 0.5mm.

Cylinder

Outer Rail Set

Chain Sheave

Chain

Anchor

Carriage Chain

Load Lowering

Flow Valve

Inter Rail Set

Primary Cylinder

Lower Roller

Inner Rail Set

Typical Triple Stage Upright Assembly

SM 765, Nov ’06

Upright Specifications and Description • 34-1-3

Group 34, Uprights

Section 2

Troubleshooting

The visual inspection and the operational checks pre-

• Dry hose sheave or rollers; check condition of all

sented in Section 3 should be used to determine problems

sheaves and rollers and lubricate as necessary.

with the upright. Possible problems, causes, and remedies

• Damaged chain sheaves; check condition of chain

are listed below.

sheaves and repair or replace.

Other troubleshooting information about the hydraulic cir-

• Excessive fork hanger or carriage fork bar wear;

cuit and components appears in the troubleshooting Sec-

inspect and replace as necessary.

tions of Groups

29 and

30. Use these other

• Seals dry; lubricate rod.

troubleshooting Sections for more detailed problem isola-

• Seals dry - all primary cylinders; remove gland and

tion with Upright hydraulic functions.

add 100 ml (3.4 oz) of hydraulic oil to rod side of

piston, see “Cylinder Removal, Shimming, Over-

! WARNING

haul, and Replacement.”

The procedures for troubleshooting uprights,

carriages, and forks involve movement of the

No lift, tilt, or auxiliary function

components. Failure to follow these warnings

can result in serious injury.

• Hydraulic fluid level low; check level and fill.

Make sure overhead clearances are adequate

• Broken hoses or fittings; check and repair.

before raising the upright to full lift height.

• Damaged or blocked sump strainer; check and

Do not walk or stand under raised forks.

clean.

Block carriage and upright whenever making

checks with the upright elevated.

• Hydraulic pump defective; see Group 29 for pump

Keep clear of load and carriage when making

troubleshooting.

any check or adjustment.

• Defective main hydraulic control valve; see Group

Keep your arms and fingers away from mov-

30 for valve troubleshooting.

ing parts of the upright.

• Defective upright load-lowering flow valve; disas-

Do not reach through open areas of the

semble valve, check and clean or replace.

upright.

No lift function but tilt operates

Upright noise

• Broken hoses or fittings; check and repair.

• Bent or broken components; inspect upright thor-

• Cylinder is damaged; inspect and repair.

oughly and repair or replace components as

required.

• Main hydraulic control valve, lift section defective;

see Group 30 for valve troubleshooting and ser-

• Damaged upright roller; check condition of rollers

vice information.

and replace defective rollers.

• Upright load-lowering flow valve damaged; disas-

• Roller scuffing rails; clean and lubricate rails.

semble valve, check and clean or replace.

• Roller (carriage or upright) shimming needs

adjustment; check and adjust as required.

• Fit between roller edge and rail flange excessively

loose in rails; replace with oversized, “Select-Fit”

rollers. See “Upright Roller Clearance Check and

Shim Adjustment.”

• Dry lift chain; lubricate chain.

SM 765, Nov ’06

Troubleshooting • 34-2-1

Group 34, Uprights

Load cannot be lifted to maximum height

• Defective priority valve; see Group 30 for valve

troubleshooting information.

• Hydraulic fluid level low, check level and fill.

• Defective upright load-lowering flow valve;

• Debris in upright; check and clean.

remove valve clean, inspect, and replace if neces-

• Hydraulic hose fittings loose or damaged; check

sary.

and torque correctly (see Group 40 for specifica-

tions) or replace.

Lowering speed sluggish

• Check cylinder for external leakage; replace cylin-

• Damaged or binding upright roller; check condi-

der if cracked.

tion of roller and replace if necessary.

• Cylinder shimming is incorrect; check and adjust

• Damaged or kinked hydraulic hose or tube; check

shimming.

condition of hose and tube, repair or replace as

• Internal leakage on lift or secondary piston cylin-

necessary.

ders; remove rod and piston and clean check

• Defective upright load-lowering flow valve; check,

valves; also clean and inspect/replace piston seals.

clean and replace valve if necessary.

See Section 5.

• Defective velocity fuse; remove fuse from cylinder

• Cylinder check valve on lift or secondary piston

hydraulic port, clean and recheck for proper opera-

cylinders not functioning properly; remove rod and

tion.

piston and clean check valves; also clean and

inspect/replace piston seals. See Section 5.

Load bounces excessively when lowering

• Hydraulic pump defective; see Group 29 for pump

• Air in hydraulic system, TSU and Hi-Lo ram-type

troubleshooting information.

cylinders; set capacity load on upright and lift form

• Upright rails binding:

fully collapsed to full lift height for 10-15 cycles.

a. Perform a visual inspection and check for worn,

• Defective upright load-lowering flow valve; check,

or distorted parts, broken or cracked rails or tie-

clean and replace valve if necessary.

bars, correct chain and hosing placement and

operation

• Defective main lift valve; see Group 30 for valve

b. Check rollers for contamination and proper oper-

troubleshooting and service information.

ation, perform roller clearance check and adjust-

• Defective velocity fuse; remove fuse from cylinder

ment

hydraulic port, clean and recheck for proper opera-

tion.

Lift speed sluggish

Upright mis-staging (TSU lifting)

• Hydraulic fluid level low; check level and fill.

• Debris in upright roller area of carriage; check and

• Broken hoses or fittings; check and repair.

clean.

• Pump inlet line restricted; remove from pump and

• Interference between carriage and inner rail or cyl-

clean.

inder; check staging alignment and adjust or repair

• Damaged or binding upright roller; check condi-

as necessary.

tion of roller and replace if necessary.

• Bent or broken carriage or inner rail; replace part -

• Internal leakage on piston-type lift and secondary

do not try to repair by welding.

cylinders (with load); perform cylinder checks

• Damaged or binding carriage roller; check condi-

listed under “Load cannot be lifted to maximum

tion of roller and replace if necessary.

height.”

• Carriage roller shimming or thrust roller out of

• Hydraulic pump defective; see Group 29 for pump

adjustment; perform roller checks on carriage and

troubleshooting information.

make adjustments as necessary.

• Defective main lift valve; see Group 30 for valve

• Damaged or kinked primary cylinder hose; check

troubleshooting and service information.

condition of hose, repair or replace as necessary.

• Defective velocity fuse; remove fuse from cylinder

• Primary cylinder chain or chain sheave binding or

hydraulic port, clean and recheck for proper opera-

damaged; inspect and repair.

tion.

34-2-2 • Troubleshooting

SM 765, Nov ’06

Group 34, Uprights

• Internal leakage in primary lift cylinder; perform

• Bent or broken carriage or inner rail; replace part -

cylinder checks listed under “Load cannot be lifted

do not try to repair by welding.

to maximum height.”

• Carriage and upright roller shimming or thrust

• Damaged primary lift cylinder causing binding in

roller out of adjustment; perform roller checks on

the cylinder; inspect and repair or replace cylinder.

upright and/or carriage and make adjustments as

necessary.

• Defective velocity fuse; remove fuse from cylinder

hydraulic port, clean and recheck for proper opera-

• Defective velocity fuse; remove fuse from cylinder

tion.

hydraulic port, clean and recheck for proper opera-

tion.

Upright mis-staging (TSU lowering)

External leakage on primary cylinder

• Debris in upright roller area or tie bar area; check

and clean.

• Gland loose; check and tighten primary cylinder

gland to 588 N⋅m (432 ft-lb) and glands on lift

• Bent or broken carriage or inner rail; replace part -

(secondary) cylinders to 392 N⋅m (289 ft-lb).

do not try to repair by welding.

• Cracked cylinder tube; replace tube.

• Damaged or binding roller on upright; check con-

dition of roller and replace if necessary.

• Rod seal damage; replace seals and check for:

- Damaged rod seal groove in gland; check for

• Carriage and upright roller shimming or thrust

damage to groove and replace seal or gland if

roller out of adjustment; perform roller checks on

necessary

upright and/or carriage and make adjustments as

- Scored cylinder wall; repair or replace cylinder

necessary.

tube if necessary

• Damaged or kinked lift cylinder hose; check condi-

- Leaking check valve; clean and replace if nec-

tion of hose, repair or replace as necessary.

essary

• Lift cylinder chain or chain sheave binding or dam-

- Leaking O-ring seal on check valve; replace

aged; inspect and repair.

check valve.

• Bent cylinder rod; inspect and replace rod and/or

• Gland static seals (O-rings and back-up ring) dam-

cylinder as necessary.

aged; replace back-up ring.

• Internal leakage in piston-type cylinders; perform

• Gland static seals sealing surface damaged; check

cylinder checks listed under “Load cannot be lifted

groove and bore and repair or replace as necessary.

to maximum height.”

• Damaged lift cylinder causing binding in the cylin-

External leakage on lift (Standard) and

der; inspect and repair or replace cylinder.

secondary cylinder (TSUs and Hi-Lo)

• Defective velocity fuse; remove fuse from cylinder

hydraulic port, clean and recheck for proper opera-

• Gland loose; check and tighten gland on cylinders

tion.

to 392 N⋅m (289 ft-lb).

• Cracked cylinder tube; inspect and replace tube.

Upright mis-staging (Standard and Hi-Lo

• Seal damage in piston-type cylinders; replace pis-

upright lowering)

ton seals and rod seals.

• Damaged seal groove, piston-type cylinders; check

• Damaged or binding roller on upright; check con-

for scratches, nicks, or burrs and repair or replace

dition of roller and replace if necessary.

rod and piston.

• Top carriage roller retaining cap screw loose;

• Scored cylinder wall, TSU piston-type cylinders;

check and replace cap screw.

replace tube and all seals.

• Lift cylinder chain or chain sheave binding or dam-

• Scored or damaged rod; replace rod and all seals.

aged; inspect and repair.

• Damaged gland back-up seal; inspect and replace

• Debris in upright roller area or tie bar area; check

seal.

and clean.

SM 765, Nov ’06

Troubleshooting • 34-2-3

Group 34, Uprights

• Gland static seals sealing surface damaged; check

• Cylinder hydraulic fittings loose or worn; check

grooves and bore.

fitting O-rings, tighten fittings according to Group

40, “Hydraulic Fitting Tightening Procedure.”

Oil leak at top of lift cylinder

• Check valve worn or damaged; remove rod and

• Scored cylinder wall; see Section 5.

piston, clean check valve and replace if necessary.

• Worn or damaged gland rod-seal; see procedures

• Control valve spool linkage malfunctioning, dam-

for piston-type cylinders under “Cylinder leaking

aged, or worn; see Group 30, Section 5 for linkage

internally.”

adjustment and/or replacement.

• Counterbalance function in main hydraulic control

Unsatisfactory lift or tilt cylinder drift test results

valve malfunctioning, damaged, or worn; inspect

• Cylinder leaking internally; remove cylinder gland

and clean or replace if necessary.

and check:

a. Primary cylinder should have only 3.4 ounces

(100 ml) on rod side of the piston

b. Piston-type lift and secondary cylinders should be

dry on rod side of piston.

If fluid is leaking past piston:

On piston-type cylinders, remove rod and piston,

clean check valves and clean and inspect/replace pis-

ton seals

See Section 5.

34-2-4 • Troubleshooting

SM 765, Nov ’06

Group 34, Uprights

Basic Visual Inspection

Lift Chains

Use the following steps to conduct an initial visual inspec-

Inspect the chains for:

tion of the upright. This is the same type of inspection

• Proper lubrication. The links should have a coat of

operators should be conducting on a daily basis.

oil on all surfaces. Lubrication oil should penetrate

If you note problems with any component during the basic

completely into chain joints.

visual inspection, continue with “Extended Inspection”

• Good condition of the chain links and pins. No

for checks and service.

rust, corrosion, stiffness, or cracking should be evi-

dent. Pins should not be turned or protruding.

! WARNING

• Excessive side wear or edge wear on the chain

The procedures for checking, maintaining,

plates.

and adjusting uprights, carriages, and forks

• Correct, equal tension on chain sets.

involve movement of the components. Failure

• Secure anchor bolt, adjustment nut, and jam nut

to follow these warnings can result in serious

mounting.

injury. Always use extreme caution.

• Correct alignment of the chain anchors to the chain

Do not walk or stand under raised forks.

and chain sheaves. Adjust turned chain anchors.

Keep clear of load and carriage when making

any check or adjustment.

• Loose, broken, or damaged anchor bolt pins and

Keep your arms and fingers away from mov-

cotter pins. Replace defective pins and cotter pins.

ing parts of the upright.

Do not reach through open areas of the

Rollers

upright.

Inspect the upright and carriage rollers for:

General

• Broken or loose rollers.

• Loose, broken, or misadjusted thrust roller on the

• Check to make sure all fasteners are secure.

carriage.

• Check to make sure the upright lifts and lowers

• Obvious signs of failed bearing seals.

smoothly with and without a capacity load.

• Check for visible damage to components.

NOTE

Some grease will purge from the bearings in

the first 100-200 hours of operation.

Forks

• Check function and security of the fork latch.

• Excessive looseness in carriage or upright roller

shimming.

• Inspect the forks for cracks, especially the hanger

and heel areas.

Upright and Carriage Weldments

• Check for wear in the fork heel. If heel wear is evi-

dent, perform the extended inspection.

Inspect the upright and carriage for:

• Inspect the fork hanger and carriage fork bar for

• Debris or foreign objects on the components.

excessive wear.

• Bent, cracked, or broken components.

• Inspect for bent forks.

• Undesirable wear on or contact between compo-

nents.

Load Backrest

• Irregular roller patterns and signs of excessive

• Inspect load backrest for damage such as cracks or

wear or scraping on the rails.

bending.

• Check for tight mounting fasteners.

34-3-2 • Upright Inspection

SM 765, Nov ’06

Group 34, Uprights

Hydraulic System

Fork Bending

Overloading, glancing blows against solid objects, or

Inspect the upright hydraulic system components for:

picking up loads unevenly can bend or twist a fork. Use

• Damage or wear on all hoses and hydraulic tubes.

the following procedure to check for fork bending.

• Leaks on hoses, fittings, or valves.

1. Place a 50 x 100 x 610 mm (2 x 4 x 24 in) wood

• Leakage on the cylinders.

block flat on the fork. Make sure the block is not rest-

ing on the heel radius.

• Excessive drift in lift or tilt operations.

Extended Inspection

The extended inspection should be performed whenever

the basic visual inspection indicates upright problems, as

specified for PMs, or at least every 2000 hours.

Forks

Forks have a limited service life because of wear and

fatigue. Forks should be tested every 50-250 hours using a

visual inspection, a fork thickness check, a fork bending

Fork Bending Check

check, and a fork gap check. If replacement is necessary,

always replace the pair to ensure fork integrity.

2. Set a carpenter’s square on the block against the fork

shank

Fork Alignment

3. Check the fork 508 mm (20 in) above the blade to

1. Park the truck on a flat, even surface, tilt upright to

make sure it is not bent more than 14.5 mm (0.6 in) at

vertical position, and set forks 25-50 mm (1-2 in)

the maximum.

above the ground.

4. If blades are bent over the 14.5 mm (0.6 in) allow-

2. Compare fork arms to be sure they are straight, on

ance they should be replaced as a set.

the same plane (level), and the same length.

See Section 7, “Fork and Carriage Removal and Replace-

3. Measure the distance from the fork tips to the

ment,” for procedures to remove and replace the forks.

ground. The height difference between the forks tips

Fork Fatigue

should be no more than 6mm(1/4in).

Fatigue cracks normally start in the heel area or on the

underside of the top hanger. If cracks are found, the fork

should be replaced. Dye penetrants or magnaflux can be

used for a more accurate inspection.

Fork Wear and Heel Wear

Industrial Truck Association (ITA) standards require that

a fork be removed from service when the blade or heel

thickness is reduced by 10% over its original thickness. If

the heel is 10% smaller than the arm, the load capacity

could be reduced by 20%. A 5,000-pound (2272 kg)

Fork Arm Height

capacity fork with 10% wear can only safely handle 4,000

4. If the fork tips are not aligned within the specified

pounds (1818 kg).

6mm (1/4in) difference, the cause of the problem

Use of fork wear calipers are recommended (Clark part

must be determined and corrected before returning

number 1803641) to gauge fork wear as follows:

the truck to service. If replacement is necessary,

always replace the forks in a set.

1. Use the outside jaws of the caliper to measure fork

thickness in the shank area of the fork.

SM 765, Nov ’06

Upright Inspection • 34-3-3

Group 34, Uprights

NOTE

A small amount of lubricant can be applied

NOTE

to the fork latch. Do not over lubricate and

allow lubricant to run down on carriage fork

Hold the caliper square and use light pres-

bar.

sure to squeeze the outer jaw tips against the

fork shank. Take care not to accidentally

2. Check fork stops for widening of notches or round-

alter the reading of the calipers.

ing of top edge. Replace the carriage if fork stops are

excessively worn.

2. Check the fork blade area to the inside jaws of the

caliper.

Lift Chains

3. If the inside jaws fit over the fork in the blade area,

wear exceeds allowable 10% wear and a new set of

The following checks should be performed every 50-250

forks should be installed.

hours to ensure correct chain performance See Section 6

Fork Hanger Wear and Carriage Fork Bar Wear

for more complete chain inspection and maintenance pro-

cedures.

Inspect the fork hangers and carriage fork bar. Excessive

wear can cause the fork to disengage the fork bars or

Chain Wear (Stretch) - All Lift Chains

reduce fork hanger life.

Lift chain stretch due to wear in the joints can be mea-

sured using a measuring tape or Clark’s chain check ruler.

Chain Check Ruler - Clark Part Number 59-960-9908

• If fork hangers are excessively worn, replace the

forks as a set.

When any section of the chain has worn and increased its

• If carriage fork bar is excessively worn, replace the

original length by 3% or more, the chain must be replaced.

carriage.

When checking chain wear, always measure a segment of

the chain that rolls over a sheave.

IMPORTANT

Welding is not recommended for repairing

forks or carriage. Replace the worn parts

with new parts.

Fork Latch and Carriage Fork Stops

1. Check fork latches for proper operation. Latches

should operate smoothly. The spring should be in

good condition and securely lock the fork into posi-

tion. Replace the fork latch if it does not operate

properly.

34-3-4 • Upright Inspection

SM 765, Nov ’06

Group 34, Uprights

IMPORTANT

WARNING

Never replace a single chain in a set. Always

replace the two chains in a set for consistent

Do not reach through the upright to push

lift operation. Always replace anchor pins

chains for tension check.

when replacing chains.

3. If one chains moves more than the other;

1. For example, measure a 305 mm (12 in) segment of

a. Lower the forks to ease tension on the chains.

the chain that does not roll over a sheave and count

b. Adjust chain adjustment nuts for equal tension on

the number of links in the segment.

both chains. See Section 6 for chain adjustment

procedures

2. Find an area of the chain that normally runs over the

sheave. This can usually be identified by wear on the

4. Repeat the tension test and make adjustments until

plate edges that roll over the sheave.

the tension is equal on both chains when the carriage

and upright are raised.

3. If the same number of links measures over 315 mm

(12.36 in) the chain must be replaced.

If using a chain check ruler, see instructions on the ruler.

Carriage and Upright Weldments

Chain replacement procedures appear in Section 6.

The carriage and upright should be checked for fatigue

cracks and bent components every 2000 hours or every

Chain Length

year..Fatigue cracks start in areas of stress after a high

IMPORTANT

number of load cycles. Stress concentrations typically

Perform a chain length check and adjust-

exist in welded joints, in the area around a welded joint, or

ment every 50-250 hours. Checks and adjust-

in the corners of parts. Dye penetrant, magnaflux, or other

ments should also be performed to adjust for

crack detection methods can be used to find or trace

chain stretch and tire wear.

cracks. If cracks are found in any structural weldment, the

component should be replaced before returning the truck

Chain length must be adjusted if:

to service.

• The fork-to-ground clearance is less than 5 mm

• Bent components indicate excessive loading or

(.20 in) or more than 25 mm (1.0 in) when the

high impacts to the weldments. Bent components

upright is vertical.

are usually structurally damaged and should be

replaced.

• The center of the bottom carriage roller comes

within 20 mm (0.80 in) of the bottom edge of the

• Inspect roller contact patterns on the rail sections.

inner rail.

Roller contact patterns should be smooth and regu-

lar.

• The carriage safety stop hits the inner rail stop at

- In some applications, it may take up to 500

full lift height.

hours of operation to develop a roller contact

• On TSUs and Hi-Lo, the difference between the

pattern on the flange of the rail.

bottom of the inner rail and the outer rail is greater

- In applications where heavy loads are common,

than 10 mm (0.40 in).

a rail lubricant may be required to allow proper

See Section 6 for chain length adjustment procedures.

wear-in on the roller.

Chain Tension

• Check rails and carriage for wear due to undesir-

able contact between components. Such contact

IMPORTANT

can be an indication of broken rollers, loose com-

Center any auxiliary attachments before

ponents, foreign objects or debris on the upright, or

beginning tension check

a broken weldment.

- If contact or rubbing exists, the condition must

1. Raise the upright enough to put tension on the chains

be corrected immediately.

to be checked.

- Rail and carriage weldments with damage

2. Push the chains forward and pull them backward; the

should be replaced.

amount of tension should be equal on both sides.

SM 765, Nov ’06

Upright Inspection • 34-3-5

Group 34, Uprights

• Tie bar areas should be free of foreign objects and

NOTE

debris. The roller area of the rail should be cleaned

Some grease will purge from the bearings in

every 500-1000 hours in a normal application.

the first 100-200 hours of operation. This is

- In applications where excessive amounts of

not necessarily a sign of a failed roller bear-

contaminants settle in the rail channels, clean-

ing seal.

ing may be required on 50-250 hour intervals.

- If excessive contamination exists, the rollers

The external thrust rollers are not adjustable. The internal

should be exposed and the bearing seal areas

thrust roller adjusts using a locking cam on the mounting

cleaned thoroughly.

cap screw. See Section 4 for roller replacement and inter-

See Section 4 for carriage roller and upright

nal thrust roller adjustment procedures.

roller removal and installation.

Carriage and Upright Main Load Rollers

Inspect the carriage and upright main load rollers for bro-

Carriage and Upright Rollers

ken, loose, or rough bearings. Defective rollers should be

replaced.

Carriage Thrust Rollers

Shoulder

The carriage uses two types of thrust rollers.

Roller shaft

• The internal thrust roller is found on both standard

shims

and TSUs. The carriage internal thrust rollers are

Bearing outer race

located on the lift bracket and run on the inside

web of the inner rail. The internal thrust roller is

intended to carry a portion of the carriage lateral

load.

• The second type of carriage thrust roller is an

Indications of broken or damaged rollers include:

external thrust roller. The external thrust roller runs

along the outside flange of the inner rail to control

• Part of all of roller bearing missing

lateral load on the carriage. External thrust rollers

• Bearing outer race loose

are found on STD, Hi-Lo CL III and TSUs.

• Scraping noise from the upright

Internal thrust roller

• Scraping of carriage fork bar on inner rail (carriage

rollers)

• Upright rail sections scraping together (upright

rollers)

• Upright misstaging

External thrust roller

(not in 2.0/2.5 ton STD

• Excessive looseness of the rail section or carriage

and Hi-Lo CL )

demonstrated by the following load test.

NOTE

Both types of thrust rollers should be checked for smooth

Some grease will purge from the bearings in

rotation, seal integrity, radial bearing tightness, and a tight

the first 100-200 hours of operation. This is

cap screw. A roller should turn smoothly without sticking

not necessarily a sign of a failed roller bear-

and be grit free. Replace the roller if any defect is found.

ing seal.

External thrust roller cap screws have a locking patch to

Load Test

prevent the cap screw from backing out. Repeated

A load test helps you to determine the amount of clear-

removal will deteriorate the ability of the patch to hold the

ance between the moving upright parts. The upright

cap screw. If the cap screw is backing out without holding,

requires some lateral movement between the interlocking

a new cap screw is recommended. The cap screw can also

rails and the carriage. But, too much or too little clearance

be cleaned and set using thread locking compound Loctite

can be the cause of binding and uneven operation.

271 (Clark Part 1802302). The internal thrust rollers use a

jam nut to ensure that the bearing remains secure.

34-3-6 • Upright Inspection

SM 765, Nov ’06

Group 34, Uprights

manufacturing tolerances and wear in the upright rail sec-

! WARNING

tions.

An upright or carriage can move unexpect-

Side Clearance

edly during service procedures causing

Roller

severe injury:

Do not walk or stand under raised forks.

Roller Shaft

Keep clear of load and carriage when making

and shoulder

any check or adjustment.

Rail Web

Keep your arms and fingers away from mov-

ing parts of the upright.

Do not reach through open areas of the

upright.

Failure to follow these warnings can result in

serious injury.

Signs of loose shimming include:

1. Excessive lateral (side-to-side) movement in the

Place a capacity load on the forks and secure it to the

upright rail sections

carriage.

2. Excessive lateral shift in the upright at, or near, full

maximum fork height (MFH)

! CAUTION

3. Irregular roller patterns on the rail.

Test load must be stacked stably, not extend

beyond the pallet, and be secured on the pal-

Signs of over shimming include:

let. Operate the truck only from within the

1. Mis-staging or hanging up of the upright

operator’s compartment.

2. Excessive wear in the rail web

Tilt the upright back slightly and raise the upright to

3. Premature bearing failure.

its maximum extension several times. Note the

Perform the following roll pattern check and the load test

smoothness of operation, the carriage play, and play

if the need for roller shimming is suspected. See Section 4

between the rails.

for detailed clearance measurement procedures.

Move the load 102 mm (4 in) off center on the forks

Roll Patterns

and resecure it to the carriage.

Impressions made by rollers on upright rails are called roll

Raise the upright to its maximum extension and

patterns. Roll patterns can provide indication of the need

lower the load to the floor several times.

for upright or carriage adjustment.

Repeat the step, moving the load 102 mm (4 in) off

center to the other side.

WARNING

Raise the upright to its maximum extension and

Keep clear of load and carriage when making

lower the load to the floor several times.

any checks or adjustments.

Carefully observe the smoothness of operation, particu-

larly in carriage play, and play between the rails. If any

1. Elevate the carriage about 4 feet (1.3 m).

unusual movement, staging, or noise occurs during the

2. Apply a light, thin layer of grease to the roller con-

test, correct the problem before returning the truck to ser-

tact area.

vice. Continue with the following roller shimming checks

if too much play is evident in the carriage and rails in the

3. Lower the forks and pick up a capacity load. Raise

load test. The troubleshooting guide may also help to

and lower the upright several times.

identify specific problems with upright operation.

4. Back out from the load and raise the carriage.

Roller Side-Clearance

Compare the impressions of the rollers on each side of the

The carriage and upright rollers are shimmed between the

upright rails. The impressions should look the same on

inner race and the roller shaft shoulder to maintain mini-

both sides. Look for signs of metal scoring or gouging

mal clearance between the side of the roller and the web

which can indicate excessive pressure caused by damaged

of the adjacent rail. Shim adjustments help accommodate

or misadjusted rollers.

SM 765, Nov ’06

Upright Inspection • 34-3-7

Group 34, Uprights

Carriage rollers, including side-thrust rollers, and all

NOTE

upright rollers can be checked by examining roll patterns.

The seals are installed with lubricant and a

If irregular impressions result from the checks, perform

trace amount will be in the gland/tube inter-

the “Lift Cylinder Shimming Check” and the “Load Test”

face area.

to further diagnose problems.

4. After cleaning the top of the gland and the barrel,

See Section 4 for procedures to measure clearances and

cycle the upright 5-10 times. If a ring of oil forms to

adjust carriage or upright rollers.

run 3 mm (0.125 in) down the rod, the cylinder must

be overhauled or replaced.

Cylinders

Internal Leakage on Primary Cylinder

Use the Drift Test, presented under “Hydraulic Checks”

To check for internal leakage on the primary cylinder:

below, for additional diagnosis of cylinder condition. See

1. Lift the upright to maximum height then lower forks

Section 5 for cylinder repair.

completely.

External Leakage (All Cylinders)

2. Cycle the upright 5-10 times through the first 2/3

To check for external leakage on the primary cylinder:

length of the primary stroke and lower forks com-

1. Clean the top of the gland and rod to remove any

pletely.

buildup of debris.

3. Slowly lift the carriage 305-610 mm (1-2 ft) into the

2. Check rod surface for defects or unusual wear.

secondary lift stage then lift to full extension.

• Nicks, burrs, or other sharp defects can cause dam-

4. If the carriage does not lift to full height, the problem

age to the seal and will lead to leaks. The rod

is likely an internal leak and the cylinder should be

should be repaired or replaced.

overhauled.

• For piston-type cylinders, small blunt defects in the

5. If the carriage does lift to full height, but you still

top and midsection of the rod can be tolerated in

suspect an internal leak, repeat the procedure with a

this cylinder design. The high pressure sealing is

40-70% capacity load.

over the last several inches of stroke. This type of

defect is acceptable if leakage is not evident.

NOTE

3. Check for external leakage from the cylinder barrel,

The primary cylinder normally has approxi-

gland O-rings and backup ring, and the rod seal.

mately 100 ml (3.4 oz) of hydraulic fluid on

the rod side of the piston as a pre-charge.

Use the Drift Test, presented under “Hydraulic Checks”

below, for additional diagnosis of cylinder condition. See

Section 5 for cylinder repair.

Internal Leakage on Piston-Type Lift and Secondary

Cylinders

To check for internal leakage in Standard lift and TSU

secondary cylinders:

1. Lift the upright to MFH then lower forks completely.

2. Cycle the upright 5-10 times through the first 2/3

length of the lift cylinder stroke and lower forks com-

pletely.

• The gland O-rings and backup ring are near-zero

3. Lift the upright to full MFH.

leakage seals. If, after cleaning the gland and tube,

Watch for the lift cylinder to increase lift speed. If you see

oil accumulates to form a run, the O-rings and

an increase in lift speed, one or both of the lift cylinders

backup ring should be replaced (see Section 5).

have an internal leak and requires overhaul.

• External leakage from the barrel requires replace-

ment of the barrel.

34-3-8 • Upright Inspection

SM 765, Nov ’06

Group 34, Uprights

If the upright does not increase lifting speed, but you still

a. Hoses or tubes with scrapes or kinks should be

suspect an internal leak, repeat the procedure with a

replaced.

capacity load. If the upright does not extend to full MFH,

b. Hoses with outer cover wear exposing the rein-

the problem is likely an internal leak and the cylinder

forcement braiding should be replaced.

should be overhauled.

Lift Cylinder Shimming

Upright Drift

The lift cylinders on both standard uprights, Hi-Lo and

Drift tests check cylinder, main valve, and hydraulic cir-

TSUs bottom out at the end of the stroke to limit upright

cuit integrity under load pressures. A load is held elevated

extension. The upright has dual lift cylinders and the cyl-

for an extended period to determine how much the upright

inders’ extension length must be equal. If not, “racking,”

“drifts” (moves) over a specified time period. A tilt cylin-

or side-to-side shifting, results. Rod extension length is

der drift test appears in Group 32, Section 2, “Tilt Cylin-

made equal by using shims under the rod end of the cylin-

der Checks and Adjustments.”

der. To determine if shimming of the cylinders is required

to prevent racking, perform the following operational

check:

WARNING

An upright or carriage can move unexpect-

! CAUTION

edly during service procedures causing

severe injury:

Make sure truck is parked on level surface

Do not walk or stand under raised forks.

with parking brake applied and wheels

Keep clear of load and carriage when making

chocked; make sure overhead clearance is

any check or adjustment.

adequate to extend upright to its full height.

Keep your arms and fingers away from mov-

ing parts of the upright.

1. Center the forks or attachments on the upright.

Do not reach through open areas of the

2. Check for equal chain tension.

upright.

Failure to follow these warnings can result in

3. Raise the upright from the retracted position to full

serious injury.

lift height. Note the point when the lift cylinders

reach the end of their stroke.

Raise upright with the rated capacity and carriage to

• If the upright shifts right or left noticeably, shim-

its full extension and lower to a point halfway down

ming is required.

from full extension with the upright substantially ver-

• Repeat the check three times before adding shims.

tical.

NOTE

Shut off the truck. Apply the parking brake and

Offset or unbalanced loads and off-center

chock the wheels.

attachments can cause the upright to shift

With a pencil or chalk, make a mark across the rails

even with proper lift cylinder shimming.

on one side of the upright.

See Section 5 for lift cylinder shimming procedure. Rack-

ing adjustments for tilt cylinders appear in Group 32, Sec-

tion 2, “Tilt Cylinder Checks and Adjustments.”

Hydraulic Plumbing

Use the Lift Cylinder Shimming Check, the Load Test,

and the following Drift Test to check the performance of

the hydraulic system.

1. Check all fittings for leakage. Disassemble fittings

and inspect the seals. Replace seals as required. See

Group 40 for hydraulic fitting tightening procedures.

Mark upright

rails here

2. Check all hoses and tubes for wear and damage.

SM 765, Nov ’06

Upright Inspection • 34-3-9

Group 34, Uprights

Consider rebuilding the cylinders if the first two remedies

! WARNING

in this list are not successful. See Section 5 for removal,

Keep clear of load and carriage when making

overhaul, and replacement procedures for primary and

any checks or adjustments. Do not use the

secondary cylinders.

upright to climb; use an approved platform.

Upright Mounting Check

4. Wait ten minutes and recheck the mark. Measure and

write down the distance the marks on the inner and

To check the Upright mounting:

intermediate rails have drifted from the mark on the

1. Check for missing, broken, bent, or loose trunnion

outer rail.

cap fasteners. Replace any damaged parts.

5. If the rated load drift 50 mm (2 in) or more in the ten

2. Lift the upright 305-610 mm (1-2 ft) and tilt the

minutes, read and follow the procedures presented in

upright fully forward.

“Drift Causes and Remedies.”

3. Check for Bushing or cap wear by inserting a feeler

gauge between the upright mounting cap and the

! CAUTION

axle-mounting bearing surface.

Test load must be stacked stably, not extend

beyond the pallet, and be secured on the pal-

let.

Drift Causes and Remedies

If drift of 50 mm (2 in) or more is evident under the rated

load, consider the following causes and remedies:

• The main hydraulic valve is misadjusted, worn, or

defective. Fluid is leaking past the valve and caus-

ing the upright cylinders to drift. See Group 30 for

hydraulic valve troubleshooting and service.

• Upright hydraulic circuit hoses or fittings are leak-

ing. Check the circuit components and repair as

necessary.

• Cylinder piston seals are worn, damaged, or defec-

tive allowing fluid past the piston causing drift.

• Primary cylinder or piston-type lift or secondary

cylinders have a check valve that allows oil to flow

back to the rod side of the cylinder. This check

valve may be clogged or defective. Inspect the

check valve for proper sealing and operation.

• The gap should not exceed 0.75 mm (0.03 in).

• If the gap exceeds 0.75 mm (0.03 in) the bearing or

cap may need replacement.

See Section 8, “Upright Removal and Replacement,” for

procedures to remove and replace the bushing.

34-3-10 • Upright Inspection

SM 765, Nov ’06

Group 34, Uprights

Section 4

Carriage and Upright Roller Clearance Checks and Shim

Adjustments

IMPORTANT

WARNING

Before removing any component for over-

haul, make sure the correct repair parts and/

Use an approved safety platform to reach the

or kits are available.

upper areas of the upright. Never use the

upright as a ladder.

! WARNING

Introduction

An upright or carriage can move unexpect-

edly:

Standard and Hi-Lo upright assemblies have two lift roller

• Do not walk or stand under raised forks

sets mounted on the rails, three lift roller sets mounted on

• Kee clear of load and carriage when mak-

the carriage, and two internal and external (except 2.0/2.5

ing any check or adjustment

ton STD) thrust roller set mounted on the carriage.

• Keep your arms and fingers away from

External thrust roller set used more than 3.0ton trucks.

moving parts of the upright.

• Block the carriage or upright when work-

The triple-stage upright assemblies have four lift roller

ing with the components in a raised posi-

sets mounted on the rails, three lift roller sets mounted on

tion.

the carriage, and two thrust roller sets (“internal” and

• Do not reach through open areas of the

“external”) mounted on the carriage. (see the “Roller Side

upright.

Clearance Chart” on next page.)

• Never attempt to move or align the rails

Each carriage and upright lift roller is nested within its

by hand. Use a prybar.

adjacent rail set. The front “face” of the lift roller handles

Failure to follow these warnings can result in

front-to-back friction and play between the nesting seg-

serious injury.

ments of the upright assembly, the side “face” of the roller

radius handles side-to-side friction and play. The rollers

SM 765, Nov ’06

Carriage and Upright Roller Clearance Checks and Shim Adjustments • 34-4-1

Group 34, Uprights

are canted (tilted) to allow the side face to bear properly

tainty that the clearance is excessive, you perform the

on the web.

checks given below.

Rail flange wear can cause excess play between the lift

To correct excessive lift roller side clearance, you add

rollers and the rail flange. The only way to correct this is

shims as described later in this Section. To correct internal

to install oversize rollers-only one size of which is avail-

thrust roller clearance, you adjust thrust roller position as

able. If oversize rollers were fitted previously, the only

described later in this Section.

remedy for excessive front-to-back play is to replace the

Gap

rail set. (carriage middle rollers are always standard-size

Lift Roller

rollers; see “Oversize Rollers” later in this Section for

details on roller replacement.)

Side Face

Shoulder

Of Clearance

The gap between the roller “side” and the web of adjacent

rail set affects the side-to-side motion of the upright-

Rail Web

which should be as small as possible without causing the

sliding segments to bind. The same is true of the internal

thrust rollers.

Rail Flange

You check the performance effect of the lift roller side

clearance and internal thrust roller clearance by means of

the load test described in Section 3. To evaluate with cer-

Roller Side Clearance Chart

Web Area

Gap at Mimimumm Span of Rail Set

Gap at Maximum Span of Rail Set

Roller Set#

Forming Gap

Target^a

Allowed^b

Target^a

Allowed^b

(mm)

(in)

(mm)

(in)

(mm)

(in)

(mm)

(in)

0.5-1.5

0.02-0.06

0.05-1.25

0.02-0.05

2.25

0-0.09

Front, Inner rail^c

Front, Inner rail

0-0.75

0-0.03

0-0.06

2.25

0-0.09

0-1.5^e

Back, Inner rail

0-0.75

0-0.03

0-1.0

0-0.04

2.25

0-0.09

Back, Inner rail

0-0.75

0-0.03

0-1.0

0-0.04

2.25

0-0.09

Back, Intermd rail

0-0.75

0-0.03

0-1.0

0-0.04

2.25

0-0.09

Back, Intermd rail

0-0.75

0-0.03

0-1.0

0-0.04

2.25

0-0.09

Back, Outer rail

0-0.75

0-0.03

0-1.0

0-0.04

2.25

0-0.09

a. Target is the desired gap after reshimming the roller set.

d. Ideal is same as final measured gap at minimum width point of rail set.

b. Allowed is the acceptable gap when checking roller set.

e. Measured at top of inner rail.

c. Internal side thrust rollers should extend 0.25-0.50mm(0.01-0.02 in)

beyond #1 rollers.

34-4-2 • Carriage and Upright Roller Clearance Checks and Shim Adjustments

SM 765, Nov ’06

Group 34, Uprights

2. Position the carriage or rails so that the roller set you

Roller Side Clearance Checks

want to check is at the mark for the narrowest span

The same basic procedure is used for checking all the lift

on the adjacent nesting rail set.

rollers. That general procedure is given in the subsection

directly below. Special instructions for specific rollers fol-

low that subsection. Follow those directions (in the sub-

section called “Directions for Checking Specific Rollers”)

Narrowest

and you will be directed to general and specific informa-

span

tion you need.

General Roller Side Clearance Checking

Widest

Procedure

span

For each roller set, you need to measure the gap between

the outside face of a roller and its adjacent nesting rail. In

general, the lift roller side clearance check procedure is as

Example of Aligning Roller Set with Widest and

follows:

Narrowest Spans Marked on Adjacent Rail Set.

Rail sets are shown separated for clarity.

1. With the spanner tool, find and mark the narrowest

and widest spans in each rail set at the roller-contact

3. Clamp the rails together opposite the roller you

areas in the rail webs:

intend to check. Use wooden shim blocks to protect

the rails. Place clamp as close to roller as possible.

• Inner Rail Set-Mark narrowest and widest spans

Torque clamp to 25 N⋅m (20 ft-lb).

for both the front and back web areas.

• Outer and Intermediate Rail Sets-Mark narrowest

and widest spans for the back web area only.

4. Measure the gap with a feeler gauge. Make sure

roller is tight against its shoulder. Write down the

result.

Web Areas on Typical Rail Set

5. Repeats steps 2 through 4 for the widest span marked

on the rail set.

Spanner Tool. Clark Part #180109

SM 765, Nov ’06

Carriage and Upright Roller Clearance Checks and Shim Adjustments • 34-4-3

Group 34, Uprights

6. If the clearance at the widest rail set span is more

Top Carriage Rollers and Internal Thrust Rollers

than 2.25 mm (0.09 in), the roller set needs shim-

The internal thrust rollers are nearly perpendicular to the

ming.

top carriage lift rollers and contact the same flange area as

If the clearance at the narrowest rail set span is more

the carriage rollers. The top carriage lift rollers and the

than 1.0 mm (0.04 in), the roller set should be

internal thrust rollers should be checked together.

shimmed; however, it is OK for the middle carriage

roller gap to be up to 1.5 mm (0.06 in).

7. Repeat entire procedure for each roller set, following

the instructions in “Directions for Checking Specific

Interral Thrust

Rollers” below.

Rollers

Directions for Checking Specific Rollers

Use these directions to supplement the general procedures

given above.

Move the top carriage lift roller to the narrowest span

Carriage Rollers

on the inner rails set.

Bottom Carriage Rollers

Clamp rail to one side as in general procedures.

Follow the general procedure above.

Check clearance of lift roller on clamped side. Locate

Middle Carriage Rollers

the clamp between the thrust roller and the bottom

roller of the carriage.

The middle rollers are difficult to access and require the

following special procedures.

1. Raise the carriage until the middle rollers are at the

top of the inner rails.

2. Measure roller side clearance at the top of the inner

rails. Note measurement here:

_____________________

If gap is less than 1.5 mm (0.06 in), shimming is not

required.

If gap is more than 1.5 mm (0.06 in), check clearance

at narrowest span by comparison with the top of the

rail set as follows:

a. With spanner tool, measure span of inner rail set

at top of the front web area. Note measurement

The internal thrust roller should contact the web and

here:

_____________________

cause the lift roller to stand off from the web by .01

b. With spanner tool, measure span of inner rail set

to 1 mm (0.001-0.03 in). If the gap is outside this

at narrowest span of front web area. Note mea-

range, the internal thrust roller must be adjusted as

surement here:

_____________________

explained later in this Section under “Internal Thrust

c. Subtract measurement in step b from measure-

Roller Adjustment.”

ment in step a, Write result here:

b-a=

_____________________

Check clearance on lift roller opposite clamped side

If the calculated gap is less than or equal to the

as in the general procedures. If clearance is greater

gap measured in step 2, the roller set does not

than 1.25 mm (0.05 in), the roller set should be

require shimming. Otherwise, the roller set

shimmed.

should be shimmed.

Move clamp to opposite side and check clearance on

clamped side as in step 2 directly above. Gap should

be 0.01-1.0 mm (0.001-0.03 in).

Move the top carriage lift roller to the widest span on

the inner rail set and check clearance as in general

procedures.

34-4-4 • Carriage and Upright Roller Clearance Checks and Shim Adjustments

SM 765, Nov ’06

Group 34, Uprights

Upright Rollers

Internal Thrust Roller Adjustment

Remove the carriage as described in Section 7 of this

The internal thrust rollers should be adjusted to extend 0-

Group.

0.75 mm (0.03 in) into the top carriage roller side clear-

Fully extend the upright making sure carriage hoses

ance. Carriage roller side clearance should be within toler-

and chains are secured out of the way to prevent

ances before you adjust the thrust rollers.

damage.

NOTE

Carriage must be replaced on upright before

! WARNING

adjusting internal thrust rollers. See Section

An upright or carriage can move unexpect-

8 for carriage replacement procedures.

edly:

• Do not walk or stand under raised forks

Lift the carriage to the top of the inner rail.

• Keep clear of load and carriage when

making any check or adjustment

Loosen the jam nut on the back of the thrust roller

• Keep your arms and fingers away from

cap screw and then loosen the cap screw. Rotate the

moving parts of the upright.

bearing to pivot toward the carriage and away from

• Do not reach through open areas of the

the rail.

upright.

• Never attempt to move or align the rails

by hand. Use a prybar.

• Use an approved safety platform to reach

the upper areas of the upright. Never use

the upright as a ladder.

Failure to follow these warnings can result in

serious injury.

Follow the “General Roller Side Clearance Checking

Procedure” given earlier in this Section.

Lower the carriage to a convenient height to do the

The clamping procedure is as illustrated below.

adjustment.

Clamp the carriage between the top and middle car-

riage roller.

• Use a shim block under the clamp on the outside of

the channel rail.

• Torque on the clamp should not exceed 25 N⋅m (20

ft-lb).

Insert a 0.5 mm (0.02 in) temporary shim between

the top carriage roller and the rail web on the side

opposite the clamp. If a 0.5 mm (0.02 in) shim will

not fit, insert a 0.25 mm (0.01 in) shim.

SM 765, Nov ’06

Carriage and Upright Roller Clearance Checks and Shim Adjustments • 34-4-5

Group 34, Uprights

Move the clamp to the shimmed side and clamp the

Oversize Rollers

rollers against the shim and the rail web by position-

ing the clamp between the top and middle carriage

At the time of roller shimming,

rollers.

you may want to replace the lift

rollers with oversize rollers to

counter rail flange wear as

detected by inspection and the

load test. Because there is only

one size of oversize rollers, you

can install them only if they were

not installed previously.

Identify oversize rollers as fol-

lows: If a roller is oversize, it has

an indented radius in the outer

Cam the thrust roller on the shimmed side against the

edge of its mounting side, as shown below.

rail clockwise and tighten the cap screws firmly.

NOTE

Lift Roller Shimming

Make sure the roller does not rotate with the

cap screw when tightening.

You need to shim lift rollers if the roller side clearance

checks indicated that clearance was excessive at either the

Insert a 0.5 mm (0.02 in) shim in the opposite roller.

narrowest or widest span of the roller set’s adjacent rail

If a 0.5 mm (0.02 in) shim will not fit, insert a 0.25

set.

mm (0.01 in) shim.

Your objective in shimming is to add only enough shims

Loosen the clamp and remove the shim.

to bring the clearances at both the widest and narrowest

spans into tolerances. In practice, you achieve this by

10.

Reposition the clamp on the opposite side and draw

shimming to obtain the smallest possible clearance at the

the roller against the shim and rail web.

narrowest span of the rail set.

11.

Cam the thrust roller on this shimmed side toward the

rail clockwise and tighten the cap screws firmly.

Carriage Roller Shimming

NOTE

Using the measurement you recorded in previously in the

Make sure the roller does not rotate with the

“Roller Side Clearance Checks,” determine the number of

cap screw when tightening.

shims required to reduce the carriage roller clearance at

the narrowest span on the inner rail to 0-0.75 mm (0-0.03

12.

Loosen the clamp and remove the shim.

in):

13.

Use a crow’s foot to torque the cap screws 70-80 N⋅m

1. Remove the carriage as described in Section 8, “Fork

(51.5-59.2 ft-lb).

and Carriage Removal and Replacement.”

NOTE

2. Remove the rollers (note the number of shims

If a crow’s foot is not available, the carriage

already on the roller shafts, if any).

can be raised to the top of the inner rail and a

socket used to tighten to the correct torque.

14.

Position the carriage to access the jam nut on the

back side of the cap screw and torque to 70-80 N⋅m

(51.5-59.2 ft-lb).

• Clean and inspect roller bearings, shims, and

shafts.

34-4-6 • Carriage and Upright Roller Clearance Checks and Shim Adjustments

SM 765, Nov ’06

Group 34, Uprights

• Replace any defective parts.

Upright Roller Removal

3. Add shims to the top and bottom rollers as deter-

1. After the carriage has been removed, lower the

mined in the previous steps.

upright rails until both of the secondary (final) lift

cylinders are completely collapsed.

• Install shims with the same number on each side.

2. Jack the truck and block under the frame so that the

• When an odd number of shims is required, always

bottom of the upright is approximately 254 mm (10

place the odd shim on the same side on all roller

in) off the floor. See “Lifting, Jacking, and Blocking”

sets.

in Group SA for safe procedures.

4. Use a straight bar to determine the number of shims

3. Set the parking brake and block the steer wheels.

to add to the middle roller shaft as shown in the fol-

lowing illustration. This shimming may be asymmet-

4. Tilt the upright to as near vertical as possible.

ric, meaning the numbers of shims do not have to

5. Using a hoist and lifting strap of adequate capacities,

match those of the top and bottom rollers.

connect the lifting strap to the inner rail on standard

and Hi-LO uprights or intermediate rails on triple-

stage uprights. Lift hoist to remove slack from the

strap.

5. Reinstall all bearings; torque top roller fasteners to

40-45 N⋅m (30-33 in-lb).

Carriage internal thrust rollers must be adjusted after the

carriage is shimmed. Adjust as described previously.

Upright Roller Shimming

Use the following procedures to remove, shim, and

replace rollers. Use the preceding checks to determine the

6. Disconnect the flow control valve manifold from the

number of shims required to reduce the roller clearances

upright bracket.

to 0.75 mm (0.03 in) or less.

! WARNING

Use an approved safety platform. Never use

the upright as a ladder.

! CAUTION

The carriage should be removed for shim-

ming or when any service is performed on the

upright. See Section 8, for removal and

replacement procedures.

SM 765, Nov ’06

Carriage and Upright Roller Clearance Checks and Shim Adjustments • 34-4-7

Group 34, Uprights

7. Disconnect the cylinder guide bolts.

Roller Removal, Shimming, and Replacement

In Hi-Lo upright, disconnect the secondary cylinder

To add shims to, or replace the rollers:

hose.

1. Use a puller to remove the rollers from the posts. Or,

gently pry the rollers off the posts. Pry at different

points around the bearing to work it off. Do not dam-

age the bearing seals on the backside of the roller.

8. Secure the cylinder to prevent its falling and discon-

nect the cylinder rod retaining bolts.

2. Inspect all roller components when removed:

a. Clean and inspect the rollers, shims, and roller

shafts.

b. Bearings should be in good condition and allow

the roller to spin smoothly with a true rotation.

c. Clean rail sections and add lubricant if necessary.

d. Replace any worn or damaged component.

3. If the clearance check indicated an even number of

shims needed, split the number evenly between the

NOTE

rollers on either side of the upright.

For 4-hose adapters, you must disconnect the

hose sheave and bracket. This is not neces-

4. If the clearance check indicated an odd number of

sary for 2-hose adapters.

shims needed, keep the odd number to the same side

on all rails of the upright. If three shims are needed,

9. Move the sheave with the hoses and any other con-

for example, add one to the rollers on the left side.

nected components out of the way.

Add the other two on the rollers on the right side.

10. Disconnect the rail cylinders by raising the rails to

5. Reposition the rollers onto the roller shaft and use a

free the cylinder rod ends from the tie bar. Tilt the

plastic or hard-rubber mallet to gently tap the roller.

cylinders inward and secure out of the way of the tie

Seat the roller evenly by continuing to tap gently

bars.

until it is fully seated and snug against the added

shims.

11. Lower the assembly completely to expose the rollers.

The lower roller set of the inner rail and upper roller set of

the outer rail on standard and triple-stage uprights are now

exposed for shim adjustment.

34-4-8 • Carriage and Upright Roller Clearance Checks and Shim Adjustments

SM 765, Nov ’06

Group 34, Uprights

Upright Reassembly

3. Reconnect the cylinder guide bolts. Do not tighten

until inner and/or intermediate rails are in the fully

The following steps detail the procedures for reassem-

lowered position. Torque guide bolts nuts to 20-25

bling the upright.

N⋅m (14.8-18.5 ft-lb).

! WARNING

The upright can move unexpectedly:

• Keep your arms and fingers away from

moving parts of the upright.

• Do not reach through open areas of the

upright.

• Never attempt to move or align the rails

by hand. Use a prybar.

Failure to follow these warnings can result in

4. Reconnect the cylinder rod retaining bolts. Torque

serious injury.

rod retaining bolts to 20-25 N⋅m (14.8-18.5 ft-lb).

In Hi-Lo upright, Reconnect the Secondary cylinder

1. Connect the lifting strap to the inner rail on standard

hose.

and Hi-Lo uprights or intermediate rails on triple-

stage uprights and raise the rails just high enough to

clear the lift cylinders. Use a prybar to guide the rails

and allow the rollers to reenter the rail channel.

5. Replace the 4-hose sheave and bracket assembly onto

the upright. Torque nuts to 20-25 N⋅m (14.8-18.5 ft-

lb).

6. Reconnect the load lowering flow valve to the

upright bracket. Torque nuts to 20-25 N⋅m (14.8-18.5

ft-lb).

2. Reposition the rail cylinders and slowly and carefully

lower the rails to seat the rod end into the mounting.

SM 765, Nov ’06

Carriage and Upright Roller Clearance Checks and Shim Adjustments • 34-4-9

Group 34, Uprights

7. Jack up the truck only enough to remove the blocking

Overshimming

and slowly lower the truck so that its full weight is on

the floor.

Use these steps to check for overshimming:

8. Replace the carriage and forks.

1. With the forks removed, lift the upright to maximum

fork height.

9. Test the upright lift and tilt functions; make sure all

upright components work correctly and smoothly.

2. Slowly lower the upright.

Check for overshimming as described in the next

• The carriage should not bind or hang up at any

subsection. Repeat the load test to make sure the

point along the rails.

upright works correctly under load. When you are

• If the carriage binds or hangs up, and the rails are

sure all components are operating correctly, perform

not clogged with grease or debris, the carriage

the chain adjustment checks in Section 3 before

requires reshimming. See “Troubleshooting” for

returning the truck to service.

other mis-staging problems.

34-4-10 • Carriage and Upright Roller Clearance Checks and Shim Adjustments

SM 765, Nov ’06

Group 34, Uprights

Section 5

Cylinder Removal, Shimming, Overhaul, and Replacement

Cylinder Types

Lift Cylinder Shimming Procedure

Standard uprights use two lift cylinders. Hi-Lo and Triple

To shim the lift cylinders to correct unequal cylinder

stage uprights use three cylinders, a primary (center-

stroke:

mounted) cylinder, and two secondary cylinders. All pri-

1. Fully lower upright until both lift cylinders are col-

mary cylinders used on Hi-Lo and triple-stage uprights

lapsed.

(TSUs) are piston cylinders. The lift and secondary cylin-

ders used on standard, Hi-Lo uprights and TSUs are either

2. Attach a hoisting strap to the tie bar of the inner rail

piston or ram cylinders.

or intermediate rail tie bar of TSUs.

IMPORTANT

Before removing any component for over-

haul, make sure the correct repair parts,

seals, and gasket sets are available.

Upright

Type

Number

Cylinder Type

<GEX20-30>

Standard pneu V2324 Piston-Type Lift Cylinder

TSU

pneu M2324 Piston-Type Secondary Cylin-

der

Hi-Lo

pneu H2317 Piston-Type Secondary Cylin-

der

! CAUTION

To remove, or partially remove, the cylinders

from the upright for shimming or overhaul,

CAUTION

start with the truck in a safe position:

Make sure hoisting equipment is of adequate

capacity and in good working order.

• Ignition off

• Parking brake applied

• Directional lever in neutral

• Forks lowered completely

• Wheels blocked.

SM 765, Nov ’06

Cylinder Removal, Shimming, Overhaul, and Replacement • 34-5-1

Group 34, Uprights

3. Remove the cylinder rod retaining bolt.

2. Disconnect and cap the hydraulic line at the base of

In Hi-Lo Upright, Remove the Cylinder Hose.

the cylinder.

Load Lowering

Flow Valve

3. Remove and discard cotter pins from chain anchor

4. Slowly lift the inner (or intermediate) rails off the top

bolt pins on the cylinder.

of the cylinder to expose the cylinder rod top.

4. Remove the pins, draw the chain through the sheave,

and drape the chain over the carriage.

! CAUTION

Block rail in up position.

5. Insert shim(s) over rod end of cylinder with the

shorter stroke to compensate for unequal stroke

length.

6. Slowly lower the inner or intermediate rail back onto

the rod ends.

! WARNING

Do not try to maneuver the cylinder or rails

with your hands. Use a prybar.

7. Replace cylinder rod retaining bolt to secure rod end

5. Remove the snap ring holding the chain sheave (and

into inner or intermediate rail mounting hole. Torque

hose bracket, if equipped) on the rod end and move

the cylinder rod retaining bolts to 20-25 N⋅m (14.8-

assembly off top of rod.

18.5 ft-lb).

8. Repeat the racking test and adjustment until no rack-

Snap Ring

ing is evident during upright lift extension.

9. Check all upright functions before returning the truck

to service.

Primary Cylinder Removal and

Replacement (Hi-Lo & TSU)

Remove the primary cylinder for replacement only. Cylin-

der can be overhauled without removing it from the

upright. See “Cylinder Overhaul” for procedures.

1. Make sure the cylinder is completely collapsed and

pressure is released.

34-5-2 • Cylinder Removal, Shimming, Overhaul, and Replacement

SM 765, Nov ’06

Group 34, Uprights

6. Disconnect cylinder mounting bolts and cylinder

4. Disconnect and cap the hydraulic line from the base

base mounting bolts.

of each cylinder. Remove the mounting bolts from

the manifold block.

Use these steps in reverse to replace the cylinder. Check

5. Lower the carriage

Group 40 for hydraulic fitting tightening procedures. If

6. Using a hoist and lifting strap of adequate capacities,

complete cylinder was torque hydraulic line bracket to 40-

connect the lifting strap to the inner rail on standard

45 N⋅m (30-33 ft-lb).

& Hi-Lo uprights and inner and intermediate rails on

triple-stage uprights.

Lift and Secondary Cylinder

Removal and Replacement

Only piston-type lift and secondary cylinders must be

removed from the upright for overhaul. The cylinder gland

and rod can be removed for overhaul while leaving the

cylinder tube mounted on the truck.

1. Make sure the cylinders are completely collapsed and

pressure is released.

2. Tilt the upright to as near vertical as possible.

3. Using a hoist and lifting strap of adequate capacities,

lift the carriage to access the hydraulic lines at the

base of the cylinders.

7. Disconnect the cylinder guide bolts.

! CAUTION

Make sure hoisting equipment is of adequate

capacity and in good working order.

SM 765, Nov ’06

Cylinder Removal, Shimming, Overhaul, and Replacement • 34-5-3

Group 34, Uprights

8. Disconnect the cylinder rod retaining bolts.

Clean the rod-end and gland thoroughly to prevent

In Hi-Lo upright, Remove the cylinder hoses.

contamination from falling into the cylinder during

disassembly.

With a blunt punch or chisel, bend the lock ring out

of the locking grooves of the gland.

Use a spanner wrench to remove the gland. Reuse the

lock ring if undamaged.

Carefully lift the rod out of the cylinder and place in

a clean area.

Inspect the tube and tube end for damage and cover

the cylinder tube end to prevent contamination.

9. Remove the cylinders by raising the inner rail (and

Remove all rings and seals from the piston and the

intermediate rail on the triple stage upright) to free

gland.

the cylinder rod ends from the tie bar.

Rod Wiper

10. Remove any shims and note number and location.

Rod Seal

O-Ring

11. Lift the cylinders off the base mount.

Back-Up Ring

Gland

Use these steps in reverse to replace the cylinders. Torque

O-Ring

the cylinder rod retaining bolts to 20-25 N⋅m (14.8-18.5

Tube

ft-lb). Torque the cylinder guide bolt nuts to 30-35 N⋅m

Rod

(22.2-25.6 ft-lb). Check Group 40 for hydraulic fitting

tightening procedures.

Spacer

Retaining Ring

Cylinder Overhaul

Check Valve

Use these steps to overhaul the primary and lift and sec-

Piston

ondary (TSU) cylinders.

Cylinder Seal

NOTE

Snap Ring

Wear Ring

During overhaul, set rod or cylinder on a

work bench with adequate support for safe

and convenient disassembly. Two sets of 4x4

in (100x100 mm) “V”-notched blocks are

helpful; one set for the cylinder barrel and

one set for the piston rod. The blocks prevent

For piston-type cylinders:

nicks and scratches from harming the piston

a. Remove the check valve from the piston for

or rod.

inspection and cleaning by removing the snap

ring from the piston bore.

Cylinder Disassembly

• To overhaul the primary cylinder, it is not neces-

sary to remove the cylinder from the upright.

Instead, free the rod end of the cylinder as

explained in “Cylinder Removal.”

• To overhaul piston-type cylinders, you should

remove the cylinders from the upright as explained

in “Cylinder Removal.” The cylinders have seals

Check Valve. Arrow shows direction of flow

on the piston, and the rods must be removed for

b. Use a blunt hook to pop the check valve out.

seal replacement.

34-5-4 • Cylinder Removal, Shimming, Overhaul, and Replacement

SM 765, Nov ’06

Group 34, Uprights

IMPORTANT

Replace the U-cup seal (groove toward bottom of

Use extreme care that you do not make nicks

cylinder), rod wiper, and O-ring and back-up seals on

and burrs on the interior surface area of the

the gland.

cap or cylinder or the piston.

Parts Inspection and Service

1. Clean all parts completely in a suitable solvent. Dry

all parts with a soft clean cloth.

2. Inspect cylinder barrel and bore for cracks, pining,

scoring, or other irregularities that may require

replacement of the barrel.

NOTE

3. Inspect the piston and rod for nicks, scratches, scor-

ing, or other defects that may demand new parts.

O-rings should be carefully installed to elimi-

nate cuts or twisting.

4. Check all gland and piston seal grooves for nicks,

burrs, and scratches that can damage seals during

Replace the piston seals:

reinstallation.

a. Primary cylinder pistons require a piston seal and

5. Inspect and clean the check valves.

wear ring. Install the piston seal from the top of

the rod. Use a ring compressor to compress the

6. Inspect all seals, including the check valve O-ring.

piston seal. This prevents damage to the seal dur-

ing reassembly.

NOTE

Minute imperfections inside the cylinder bar-

rel or on the piston or rod may be improved

for acceptable use by careful honing. How-

ever, removal of material that produces a

notch, groove, or out-of-roundness may cause

excessive leakage during operation and a

shortened life.

7. Use new parts as necessary. Always use the Packing

Kit listed in the parts manual. New kits include all

b. Piston-type lift and secondary cylinder require a

the seals, wiper rings, wear rings and O-rings neces-

cylinder seal, a back-up ring, and a wear ring on

sary for the particular cylinder.

the piston. Install the cylinder seal from the top of

the rod.

Cylinder Reassembly

Take care when installing these parts to make sure that no

parts are damaged.

1. Coat all packing, seals and rings in clean, hydraulic

oil (Clark part number 1800236 qt., 1802155 gal.)

prior to reassembly. Coat the inside of the gland nut

bore with hydraulic oil.

For protection against corrosion, lubricate spacers

(where used) with petroleum-based hydraulic fluid.

Slide the spacer onto the rod.

SM 765, Nov ’06

Cylinder Removal, Shimming, Overhaul, and Replacement • 34-5-5

Group 34, Uprights

5. Insert the piston and rod into the cylinder. Be careful

8. Check the assembly by making sure the piston slides

not to scratch or damage the cylinder gland nut

freely in and out of the cylinder.

threads.

9. Tighten the gland nut:

6. For primary cylinders, add 3.4 oz (100 ml) of hydrau-

• On primary cylinders, tighten the gland nut to 135

lic oil into the cylinder on the rod side of the piston.

N⋅m (100 ft-lb).

7. Install the lock ring onto the gland. Lubricate cylin-

• On lift and secondary cylinders, tighten the gland

der threads and screw gland onto cylinder. Be careful

nut to 100 N⋅m (75 ft-lb).

not to damage gland seal. Make sure the gland is

This competes the cylinder repair procedure. Replace the

fully seated on the cylinder barrel. Deform the lock

cylinders as described in “Cylinder Removal and Replace-

ring into slots in the tube and the gland.

ment.” Complete the chain length adjustment in Section 3

for correct carriage and rail position. When all adjust-

ments are completed, return the truck to service.

Hi-lo and Triple-Stage Upright

Typical Piston-Type Standard

Hi-lo Upright Lift and TSU

Upright Lift and TSU

Primary Cylinder

Secondary Cylinder

34-5-6 • Cylinder Removal, Shimming, Overhaul, and Replacement

SM 765, Nov ’06

Group 34, Uprights

in this condition, a pin, or series of pins, can begin to twist

Periodic Inspections

out of a chain resulting in failure. The pin head rivets

Each 50-250 hours of operation (more frequently in severe

should be examined to determine if the "VEE" flats are

or extreme environments), chains should be inspected and

still in correct alignment. Chain with rotated/displaced

lubricated. Inspection should focus on the following:

heads or abnormal pin protrusion should be replaced

immediately. Do not attempt to repair the chain by weld-

ing or driving the pin(s) back into the chain. Once the

Elongation

press fit integrity between outside plates and pins has been

When a length of 12.00 inches (305 mm) of new chain has

altered, it cannot be restored. Any wear pattern on the pin

elongated to a length of 12.360 inches (315 mm), it should

heads or the sides of the link plates indicates misalign-

be discarded and replaced. It is important to measure the

ment in the system. This condition damages the chain and

chain in the section that moves over the sheaves because it

increases frictional loading, and should be corrected.

receives the most frequent articulation. Measuring the

chain near its clevis terminals could give an erroneous

reading as it would not have flexed as frequently, if indeed

at all, as nearer the middle of the assembly.

Turned pins and abnormal pin protrusion.

Chains should be replaced when wear exceeds 3% or

Cracked Plates

when 12 inches (305 mm) of chain is stretched 3/8 inch

The chains should periodically be inspected very care-

(10 mm).

fully, front and back as well as side to side, for any evi-

dence of cracked plates. If any one crack is discovered, the

Edge Wear

chain(s) should be replaced. It is important, however, to

determine the causes of the crack before installing new

Check the chain for wear on the link plate edges caused by

chain so the condition does not repeat itself.

running back and forth over the sheave. The maximum

reduction of material should not exceed 5%. This can be

• Fatigue Cracking - Fatigue cracks are a result of

compared to a normal link plate height by measuring a

repeated cyclic loading beyond the chain's endur-

portion of chain that does not run over the sheave. Dis-

ance limit. The magnitude of the load and fre-

torted or battered plates on leaf chain can cause tight

quency of its occurrence are factors which

joints and prevent flexing.

determine when fatigue failure will occur. The

loading can be continuous or intermittent (impulse

load).

Worn contours and worn surfaces on the outside links or

pin heads should not exceed 5% of new link height.

Fatigue cracks generally run from the pin hole toward the

edge of the link plate approximately 90o from the line of

pull.

Turning or Protruding Pins

Fatigue cracks almost always start at the link plate

Highly loaded chain operating with inadequate lubrication

pin hole (point of highest stress) and are perpendic-

can generate abnormal frictional forces between pin and

ular to the chain pitch line. They are often micro-

link plates. In extreme instances, the torque could surpass

scopic in their early stage. Unlike a pure tensile

the press fit force between the pins and the outside plates,

failure, there is no noticeable yielding (stretch) of

resulting in pin rotation. When chain is allowed to operate

the material.

SM 765, Nov ’06

Upright Chain Inspection, Adjustment, and Replacement • 34-6-3

Group 34, Uprights

• Stress - Corrosion Cracking - The outside link

Ultimate Strength Failure

plates, which are heavily press fitted to the pins,

are particularly susceptible to stress corrosion

This type of failure is caused by overloads far in excess of

cracking. Like fatigue cracks, these initiate at the

the design load.

point of highest stress (pin hole) but tend to extend

in an arc-like path between the holes in the pin

plate.

Broken plate caused by overload.

Arc-like cracks in plates are a sign of stress corrosion.

Tight Joints

More than one crack can often appear on a link

All joints in leaf chain should flex freely. Tight joints

plate. In addition to rusting, this condition can be

resist flexure and increase internal friction, thus increasing

caused by exposure to an acidic or caustic medium

chain tension required to lift a given load. Increased ten-

or atmosphere.

sion accelerates wear and fatigue problems.

Stress corrosion is an environmentally assisted fail-

ure. Two conditions must be present: a corrosive

agent and static stress. In the chain, static stress is

present at the pin hole due to the press fit pin. No

cyclic motion is required, and the plates can crack

during idle periods. The reactions of many chemi-

If lubrication does not loosen a tight joint, the chain may

cal agents (such as battery acid fumes) with hard-

have corrosion and rust problems or bent pins and must

ened steel can liberate hydrogen which attacks and

be replaced.

weakens the steel grain structure.

See Section 3 for detailed chain stretch, length, and ten-

For this same reason, never attempt to electroplate

sions checks.

a leaf chain or its components. The plating process

liberates hydrogen, and hydrogen embrittlement

cracks will appear. These are similar in appearance

Chain Length Adjustments

to stress corrosion cracks.

If a plated chain is required, consult Clark. Plated

WARNING

chains are assembled from modified, individually

An upright or carriage can move unexpect-

plated components which may reduce the chain

edly:

rating.

• Do not walk or stand under raised forks

• Corrosion Fatigue - Corrosion fatigue cracks are

• Keep clear of load and carriage when mak-

very similar (in many cases identical) to normal

ing any check or adjustment

fatigue cracks in appearance. They generally begin

• Keep your arms and fingers away from

at the pin hole and move perpendicular (90°) to the

moving parts of the upright.

chain pitch line.

Corrosion fatigue is not the same as stress corro-

• Block the carriage or upright when work-

sion. Corrosion fatigue is the combined action of

ing with the components in a raised posi-

an aggressive environment and a cyclic stress (not

tion.

a static stress alone, as in stress corrosion).

• Do not reach through open areas of the

upright.

• Never attempt to move or align the rails by

hand. Use a prybar.

Failure to follow these warnings can result in

serious injury.

34-6-4 • Upright Chain Inspection, Adjustment, and Replacement

SM 765, Nov ’06

Group 34, Uprights

Standard Upright Chain Length Adjustment

3. Carriage stop-to-upright:

a. Lift upright to its full height and check for clear-

To adjust chain length on the standard upright use the fol-

ance on the carriage safety stop.

lowing illustration and procedures:

b. If the carriage stop hits the upright stop, adjust

the chain anchor adjustment nuts out until there is

at least 3 mm (0.12 in) clearance between the

stops.

IMPORTANT

The carriage stop must not be allowed to con-

tact the upright stop under any circumstance

during normal operations.

Adjust chain

length here

To carriage

If all three chain length requirements listed above cannot

be met, the tire diameter may be out of the design range

1. Fork-to-ground clearance:

allowance. Also, excessive tire wear will decrease carriage

a. Set the upright to vertical position.

stop clearance.

b. Break the jam nuts loose on the chain anchors.

Oversized tires will reduce the bottom carriage roller

engagement on the inner rail when the carriage is in the

lowered position. The fork-to-ground clearance can devi-

ate from the 10-20 mm (0.40-0.80 in) allowance by a

small amount if necessary to maintain the safe 20 mm

(0.80 in) clearance of the bottom carriage roller to the

lower edge of the inner rail.

Triple-Stage and Hi-Lo Upright Chain

Length Adjustments

c. Turn the chain adjustment nuts until clearance

Triple-stage uprights use two chain sets; one set for car-

between forks and ground is 10-20 mm (0.40-

riage lift and one set for rail lift. Adjustment anchors for

0.80 in).

the lift cylinder stage are located at the back of the outer

rail. Adjustment anchors for the primary lift stage are

IMPORTANT

behind the primary cylinder. Carriage chain anchors are

For all chain anchor adjustments:

not intended for adjustment.

• Threaded chain anchors must be left free to

pivot in mounting hole.

Hi-Lo Uprights use one chain set for carriage lift.

• Anchor cotter pin heads must be to the

For TSU inner rail lift chains, chain length must be

inside of the upright.

adjusted if the difference between the bottom of the inner

• Torque jam nuts to adjustment nuts to

rail and the outer rail is greater than 10 mm (0.40 in).

100-200 N⋅m (74-148 ft-lb).

• Make sure chain anchors are secured so

For the TSUand Hi-Lo primary cylinders lift chain, the

that no twist is evident in the chains.

chain length must be adjusted if:

2. Carriage roller position:

• The fork-to-ground clearance is less than 5 mm

a. Raise carriage about 1 m (3.2 ft) and smear a

(0.20 in) or more than 25 mm (1.0 in) when the

bead of grease on the bottom 75 mm (3 in) inner

upright is vertical.

rail in the area of the roller pattern.

• The center of the bottom carriage roller comes

b. Tilt upright fully back and completely lower.

within 20 mm (.80 in) of the bottom edge of the

c. Raise carriage about 1 m (3.2 ft) and measure the

inner rail.

distance from where the center of the bottom car-

• The carriage safety stop hits the inner rail stop at

riage roller stopped to the bottom edge of the

full lift height.

inner rail. Distance should not be less than 20 mm

(0.80 in) or chain length adjustment is required.

SM 765, Nov ’06

Upright Chain Inspection, Adjustment, and Replacement • 34-6-5

Group 34, Uprights

To adjust the cylinder lift chains on a TSU use the follow-

IMPORTANT

ing illustration and procedures:

For all chain anchor adjustments:

• Threaded chain anchors must be left free to

pivot in mounting hole.

• Anchor cotter pin heads must be to the

inside of the upright.

• Torque jam nuts to adjustment nuts to

100-200 N⋅m (74-148 ft-lb).

• Make sure chain anchors are secured so

that no twist is evident in the chains.

Adjust chain

length here

Carriage roller position:

a. Raise carriage about 1 m (3.2 ft) and smear a

To inner rail

bead of grease on the bottom 75 mm (3 in) of the

inner rail in the area of the roller pattern.

1. Set the upright in the vertical position.

b. Tilt upright fully back and completely lower.

2. Break the jam nuts loose on the chain anchors.

c. Raise carriage again about 1 m (3.2 ft) and mea-

sure the distance from where the center of the

3. Adjust the chain anchor adjustment nuts until the

bottom carriage roller stopped to the bottom edge

bottom of the inner rail is within 2.5 mm (0.10 in) of

of the inner rail. Distance should not be less than

the bottom of the outer rail.

20 mm (0.80 in) or chain length adjustment is

To adjust the primary cylinder lift chain on TSU and Hi-

required.

Lo use the following illustration and procedures:

Carriage stop-to-upright:

a. Lift upright to its full height and check for clear-

ance on the carriage safety stop.

b. If the carriage stop hits the upright stop, adjust

the chain anchor adjustment nuts out until there is

at least 3 mm (0.12 in) clearance between the

stops.

IMPORTANT

The carriage stop must not be allowed to con-

tact the upright stop under any circumstance

during normal operations.

To carriage

If all three chain length requirements listed above cannot

be met, the tire diameter may be out of the design range

allowance. Also, excessive tire wear will decrease carriage

Adjust chain

length here

stop clearance.

Oversized tires will reduce the bottom carriage roller

1. Fork-to-ground clearance:

engagement on the inner rail when the carriage is in the

a. Set the upright to vertical position.

lowered position. The fork-to-ground clearance can devi-

b. Break the jam nuts loose on the chain anchors.

ate from the 10-20 mm (0.40-0.80 in) allowance by a

c. Turn the chain adjustment nuts until clearance

small amount if necessary to maintain the safe 20 mm

between forks and ground is 10-20 mm (0.40-

(0.80 in) clearance of the bottom carriage roller to the

0.80 in).

lower edge of the inner rail.

34-6-6 • Upright Chain Inspection, Adjustment, and Replacement

SM 765, Nov ’06

Group 34, Uprights

Failure to follow these warnings can result in

Chain Lubrication

serious injury. See “Lifting, Jacking, and

Like all bearing surfaces, the precision-manufactured,

Blocking” for safe blocking procedures.

hardened-steel, joint-wearing surfaces of leaf chain

require a film of oil between all mating parts to prevent

General Guidelines

accelerated wear.

Maintaining a lubricant film on all chain surfaces will:

• Chain Movement - Make sure that the chain oper-

ating path is clear and that the chain articulates

• Minimize joint wear.

freely through its full range of operation.

• Improve corrosion resistance.

• Lubrication - Assure that the chain is well lubri-

• Reduce the possibility of pin turning.

cated with the heaviest oil that will penetrate the

• Minimize tight joints.

void between the link plate apertures and the pins.

• Promote smooth, quiet chain action.

• Paint - Make sure the chain does not get painted

over at any time.

• Lower chain tension by reducing internal friction

in the chain system.

• Protection - Where necessary, as a protection from

atmosphere or sliding wear, the chain may be cov-

Laboratory wear tests show #40 oil to have greater ability

ered with a layer of grease. It should be noted,

to prevent wear than #10 oil. Generally, the heaviest

however, that the grease will have to be removed at

(highest viscosity) oil that will penetrate the joint is best.

a later date for chain inspection and relubrication.

Whatever method is used, the oil must penetrate the chain

• Chain Mountings - Double check to be sure all

joint to prevent wear. Applying oil to external surfaces

chain fastening devices are secured and all adjust-

will prevent rust, but oil must flow into the live bearing

ments have been made to assure uniform loading

surfaces for maximum wear life.

of multiple chain applications. Check chain

anchors and pins for wear, breakage, and misalign-

To prepare the chain for oiling, the leaf chain plates

ment. Damaged anchors and pins should be

should be brushed with a stiff brush or wire brush to clear

replaced.

the space between the plates so that oil may penetrate the

live bearing area.

• Sheaves - Sheaves with badly worn flanges and

outside diameter should be replaced. This wear

Oil may be applied with a narrow paint brush or directly

may be due to chain misalignment or frozen bear-

poured on. Chain should be well flooded to be sure the oil

ings.

penetrates the joint.

In locations difficult to reach, it may be necessary to use a

Lift Chains (Standard and TSUs)

good quality oil under pressure such as an aerosol can or

pump pressure spray.

To remove and replace the lift cylinder and/or carriage

chain set on standard and triple-stage uprights (TSU):

Chain Removal and Replacement

1. Attach a hoist strap on the carriage of the standard

upright or inner rail of the TSU.

! WARNING

2. Lift the carriage or inner rail slightly to create slack

in the chains. Block the carriage or inner rail up for

The procedures for removing and replacing

safety.

chain sets involve hoisting and blocking com-

ponents.

3. Remove the chain anchor pins on the outer rail and

pull the chains off of the sheaves on the inner or

• Do not walk or stand under raised forks.

intermediate rails.

• Keep your arms and fingers away from

moving parts of the upright.

• Do not reach through open areas of the

upright.

SM 765, Nov ’06

Upright Chain Inspection, Adjustment, and Replacement • 34-6-7

Group 34, Uprights

4. Remove the chain anchor pins from the carriage on

2. Remove the chain anchor pins from the back of the

the standard upright or the inner rail on the TSU. On

primary cylinder. Pull the chains through the chain

the TSU, the inner rails must be lowered to the floor

sheave and lay over the carriage load backrest.

to access the chain anchor pins.

3. Remove the chain anchor pins from the back of the

Lift Chain Removal from Carriage (standard upright)

carriage.

Triple-Stage Upright Lift Chain Removal from Inner Rail

4. Use these steps in reverse to replace the primary cyl-

inder/carriage chain.

NOTE

Perform the chain length adjustment and chain tension

If a hose adapter assembly is used, the chain

check before returning the truck to service.

sheaves must be loosened and removed to

prevent the hoses from stretching when the

inner rails of the TSU are lowered to access

Other Chain Service Notes

the chain anchor pins.

• Use lengths of factory assembled chain. Do not

5. Use the steps in reverse order to replace the lift chain

build lengths from individual components.

set.

• Do not attempt to rework damaged chains by

replacing only the components obviously faulty.

The entire chain may be compromised and should

Primary Cylinder/Carriage Chains (TSU

be discarded.

and Hi-Lo)

• Never electroplate assembled leaf chain or its com-

1. Tilt the upright forward, lower it, and completely col-

ponents. Plating will result in failure from hydro-

lapse the primary cylinder to create slack in the

gen embrittlement. Plated chains are assembled

chains. The carriage may also be lifted and blocked

from modified, individually plated components.

in position and the primary cylinder completely col-

• Welding should not be performed on any chain or

lapsed to create slack in the chains.

component. Welding spatter should never be

allowed to come in contact with chain or compo-

nents.

• Leaf chains are manufactured exclusively from

heat treated steels and therefore must not be

annealed. If heating a chain with a cutting torch is

absolutely necessary for removal, the chain should

not be reused.

34-6-8 • Upright Chain Inspection, Adjustment, and Replacement

SM 765, Nov ’06

Group 34, Uprights

Section 7

Fork and Carriage Removal and Replacement

Lift tip of each fork and put a 100 x 100 mm (4 x 4

! CAUTION

in) block under the fork arm near the heel.

SAFE PARKING. Before working on truck:

CAUTION

1. Park truck on a hard, level, and solid sur-

face, such as a concrete floor with no gaps

Forks weight 44-99 kg (97-220 lbs) each. Take

or breaks.

care when lifting.

2. Put upright in vertical position and fully

lower the forks or attachment.

3. Put all controls in neutral. Turn key

switch OFF and remove key.

4. Apply the parking brake and block the

wheels.

Fork Removal

NOTE

Blocking the Fork

Forks do not need to be removed to remove

the carriage.

Push down on tips of the forks to disengage the fork

hooks from the carriage fork bar.

Release the fork latches.

Lift fork heel and remove block.

CAUTION

Forks are not stable sitting free in upright

position. Use care when working around the

forks.

Latch Operation

Back the truck away from the forks.

Move each fork to the notch on the bottom of the

lower carriage cross bar.

Fork Replacement

Carefully drive truck up close to forks.

! CAUTION

Forks are not stable sitting free in upright

position. Use care when working around the

forks.

Drag forks into position close to carriage and to line

up with the notche on the lower carriage cross bar.

Lift fork heel and place block under arm near the

heel.

SM 765, Nov ’06

Fork and Carriage Removal and Replacement • 34-7-1

Group 34, Uprights

4. Lift tips of forks to engage the fork hooks on the

WARNING

upper carriage fork bar.

You may need to pull on the hoses/cables and

5. Remove blocks from under fork.

chains while lowering the primary cylinder to

6. Check fork latches when repositioning forks to upper

get it all the way down. This is done to create

carriage fork notches.

slack in hoses/cables and chains and to dis-

place as much oil as possible, which will

reduce oil loss when disconnecting hydraulic

Carriage Removal

lines for auxiliary components.

The carriage should be removed for shimming or when

You may need a helper to hold the control

any service procedure is performed on the upright.

handle in the lowering position while you pull

on the carriage chains to fully collapse the

! WARNING

primary cylinder (on Hi-Lo & TSUs). When

The procedures for checking, maintaining,

pulling on the chains to lower the primary

and adjusting uprights, carriages, and forks

cylinder (on Hi-Lo & TSUs), the ignition

involve movement of the components.

must be off.

• Do not walk or stand under raised forks.

Once the carriage is fully lowered, clamp the front of

one fork to the pallet to prevent the carriage from

• Keep clear of load and carriage when mak-

falling over backwards when removed.

ing any check or adjustment.

• Keep your arms and fingers away from

moving parts of the upright.

• Do not reach through open areas of the

upright.

• Always use a prybar to move the upright or

carriage.

Failure to follow these warnings can result in

serious injury.

1. Set upright tilt to 0 degrees (vertical). Raise the car-

riage about 12 in (305 mm).

2. Place a heavy pallet under the forks. Turn the key off.

3. Lower the carriage onto the pallet and keep lowering

(until the primary cylinder is all the way down on

For carriage auxiliary components, the hose sheave

TSUs and Hi-Lo). Before proceeding with the next

bracket must be unbolted from the primary cylinder

step read the following warning.

chain sheave bracket. Move the hose bracket off the

chain bracket.

34-7-2 • Fork and Carriage Removal and Replacement

SM 765, Nov ’06

Group 34, Uprights

6. Disconnect the carriage chains at the base of the car-

10. Remove steer wheel blocks. Release the parking

riage. Pull chains back off primary cylinder sheave.

brake and slowly back the truck away from the car-

riage.

11. Lower the upright rails until both of the secondary

cylinders are completely collapsed.

Carriage Replacement

To replace the carriage:

1. First check to be sure the carriage is securely

clamped to the pallet.

7. For carriage auxiliary components, disconnect hoses

2. Move the truck up to the carriage assembly with the

(2- or 4-hose assemblies) from carriage. Remove the

inner rail centered on the carriage.

bolts and strap fixture also.

3. Raise the upright until the inner rail is high enough to

clear the upper carriage rollers.

4. Tilt the upright until it is at the same angle as the car-

riage assembly.

5. Now slowly move the truck forward until the inner

rail is centered over the carriage rollers.

• Cap all lines to prevent leaks.

• Label all lines and fittings for correct reassembly.

8. Elevate the primary cylinder to its maximum height.

Be sure all hoses and loose parts are secured out of

the way to prevent damage.

9. Continue elevating the upright until the inner rail

clears the carriage.

SM 765, Nov ’06

Fork and Carriage Removal and Replacement • 34-7-3

Group 34, Uprights

10. Reconnect the hoses and mounting strap to the car-

! WARNING

riage auxiliary component if the carriage is so

Never attempt to move or align the carriage

equipped.

or bearings by hand. Use a pry bar.

6. Lower the upright until the inner rail clears all of the

carriage rollers.

NOTE

If the rail or bearings bind, raise the upright,

back away from the carriage and check to be

sure the carriage rollers are installed prop-

erly.

7. When the inner rail has cleared the carriage rollers,

continue to lower the upright until the lift cylinders

are lowered completely.

• Lubricate all O-rings with a light coating of system

8. Reset the truck in a safe position:

hydraulic fluid or a compatible oil.

• Ignition off

• Use two wrenches to tighten hose fittings to pre-

• Parking brake applied

vent hoses from twisting.

• Directional lever in neutral

• See Group 40 for hydraulic fitting tightening pro-

cedures.

• Forks completely lowered

• Block steer wheels.

11. Adjust carriage height according to Section 6 and

chain tension according to Section 3.

9. Reinstall the carriage lift chains to the base of the

carriage.

12. Remove the “C” clamp from the pallet and check the

operation of the carriage and the upright. Carefully

check for oil leaks. Make sure the carriage and

upright work smoothly and correctly before returning

the truck to service.

• Set anchor bolts so that no twist develops in the

chains.

• Anchor pin heads must be pointing to the inside of

the upright.

• Use new cotter pins.

IMPORTANT

Always use new anchor pins when replacing

chain sets.

34-7-4 • Fork and Carriage Removal and Replacement

SM 765, Nov ’06

Group 34, Uprights

Section 8

Upright Removal and Replacement

This Section describes how to remove the entire upright

CAUTION

assembly from the truck. The carriage and forks must be

removed from the upright assembly before the upright is

SAFE PARKING. Before working on truck:

removed. (For uprights with an auxiliary component, a

1. Park truck on a hard, level, and solid sur-

side-shifter for example, the two hydraulic hoses power-

face, such as a concrete floor with no gaps

ing the auxiliary component must be removed before the

or breaks.

carriage is removed.) See Section 7, “Fork and Carriage

Removal and Replacement,” for procedures to remove the

2. Put upright in vertical position and fully

carriage and fork assembly from the upright.

lower the forks or attachment.

3. Put all controls in neutral. Turn key

switch OFF and remove key.

4. Apply the parking brake and block the

wheels.

Nipple-grease

Outer rail set

Bushing

Bolt of upright mounting

Mounting cap

Typical Upright Installation

SM 765, Nov ’06

Upright Removal and Replacement • 34-8-1

Group 34, Uprights

2. Disconnect and cap hydraulic line at the load-lower-

Upright Removal

ing flow valve. Secure the hose out of the way of the

The following procedures are for uprights with carriage

upright.

and forks, or auxiliary components removed. See Section

7, “Fork and Carriage Removal and Replacement,” for

instructions on removing the forks and carriage.

Remove the

mounting bolts

! WARNING

from the manifold

The upright assembly is heavy. Use only

hoists with enough capacity to lift the entire

assembly. Keep clear of the assembly as it is

Disconnect

and cap line from

being hoisted and set down. Keep hands and

main hydraulic

feet away from the assembly. Use prybars to

control valve.

move the assembly into position for reattach-

ment.

1. Attach a hoist and strap of adequate capacity to the

NOTE

upright as shown below. Tension the hoist so that the

For two-hose adapter assemblies, the hydrau-

upright cannot fall when upright mounting pins and

lic lines to the upright must also be discon-

tilt cylinder pins are removed.

nected and capped.

Disconnect

lines here

34-8-2 • Upright Removal and Replacement

SM 765, Nov ’06

Group 34, Uprights

2. Install rod end pins, lock plates, and fasteners.

NOTE

Tighten lock plate fasteners to a torque of 40-45 N⋅m

Reconnect two-hose adapter assembly

(30-33 ft-lb).

hydraulic lines to the upright-mounted

bracket.

Tilt cylinder

Rod end

Tilt cylinder

Mounting

Tilt cylinder

mounting Bolt

Reconnect

lines here

4. Remove the lift chain between the upright and hoist.

5. Completely check all upright and hydraulic compo-

nents under load before returning the truck to service.

3. Attach hydraulic lines to the upright flow control

valve:

6. See Section 8, “Fork and Carriage Removal and

Replacement,” for steps to replace the carriage and

fork assembly.

Connect the

mounting bolts

to the manifold

Reconnect

line here

• Lubricate all O-rings with a light coating of system

hydraulic fluid or a compatible oil.

• Use two wrenches to tighten hose fittings to pre-

vent twisting lines.

• See Group 40 for hydraulic fitting tightening pro-

cedures.

34-8-4 • Upright Removal and Replacement

SM 765, Nov ’06

Group 38, Counterweight and Chassis

Specifications

General Maintenance

Fastener Torques

WARNING

The counterweight is extremely heavy. Do not

Counterweight Mounting Bolts: 340-380 N.m (25l-280

remove the counterweight unless you have

lb-ft)

training and are familiar with the correct

procedures. Counterweights can fall if not

Description

handled correctly and can cause severe

injury or death. Keep your hands, feet, and

The counterweight is a solid, cast-iron piece mounted to

body clear of the counterweight at all times.

the back of the lift truck. It is used to counterbalance the

Hoisting equipment must be capable of han-

loads placed on the upright at the front of the truck. The

dling the weight of the counterweight when

weight must be great enough to counteract forward tip-

removing or replacing. Make sure your lift-

ping when lifting or stopping with a capacity load. The

ing equipment is of adequate capacity to han-

battery provides much of the counterweight on an electric

dle the weight.

truck.

The counterweight must be maintained in good condition

! WARNING

and securely attached to the lift truck. Because of its

heavy weight and bulky mass, the counterweight must be

The minimum battery weight for your truck

carefully supported and handled. When removed from the

is stamped on the nameplate. Never operate

truck, store at floor level as shown below to be sure it will

the truck with a battery that weighs less.

not fall or tip, causing damage or injury.

Large, hardened steel bolts hold the counterweight to the

frame.

Different counterweights are used based on truck capacity

and battery compartment length.

Counterweight weights(GEX):

Short wheel base

Long wheel base

28.2 BC

33.9 BC

560 kg (1235 lbs)

GEX20

760 kg (1675 lbs)

GEX25

720 kg (1587 lbs)

GEX30

Generic Illustration

38-1-2 • Counterweight Specifications and Description

SM 765, Nov ’06

Group 38, Counterweight and Chassis

Raise the hood of operator's seat, and remove the bat-

Counterweight Removal

tery

! CAUTION

Install the eyebolt in the counterweight. The eyebolt

should bear 1193kg(2630lb).

SAFE PARKING. Before working on truck:

Using an overhead hoist with sufficient lifting capac-

1. Park truck on a hard, level and solid sur-

ity, attach hoist chain to eye bolt. Slowly lift hoist

face, such as a concrete floor with no

until slack is removed from chain.

gaps or breaks.

Remove the counterweight mounting bolts.

2. Put upright in vertical position and fully

Counterweight mounting fastner

lower the forks or attachment.

3. Put all controls in neutral. Turn key

switch OFF and remove key.

4. Apply the park brake and block the

wheels.

! WARNING

Observe proper, safe lifting practices when

lifting counterweight on or off truck.

Counterweight should only be lifted by

appropriately-sized eye bolt installed

through the top lifting hole.

Counterweight mounting fastner

Use only overhead lifting equipment having a

safe lifting capacity in excess of that of the

counterweight.

WARNING

Remove the Electronic Controls cover.

Stand clear of the counterweight as it is being

hoisted, moved, or mounted.

Remove the controller from the counterweight.

Remove the battery connector from the counter-

Slowly lift the counterweight from the truck frame

weight.

until it is free from the counterweight hooks on the

frame and can be moved back to clear the eleclronic

controls. Take care not to damage the controls.

Slowly lower the counterweight onto a sturdy pallet.

Set the counterwcighl on its flat side if possible.

Generic Illustration

38-2-2 • Counterweight Removal and Installation

SM 765, Nov ’06

Group 38, Counterweight and Chassis

Overhead Guard Installation

! CAUTION

1. Put overhead guard in place on the truck chassis.

SAFE PARKING. Before working on truck:

2. Install the eight overhead guard mounting bolts.

1. Park truck on a hard, level and solid sur-

face, such as a concrete floor with no

Tighten to 88-95 N⋅m (65-70 lb-ft).

gaps or breaks.

2. Put upright in vertical position and fully

lower the forks or attachment.

3. Put all controls in neutral. Turn key

switch OFF and remove key.

4. Apply the park brake and block the

wheels.

Overhead Guard Removal

1. Remove the battery.

2. It is not anticipated that it should be necessary to

remove the overhead guard from the truck in thc-

coursc of normal service or repair. The instrument

panel/cowl assemblies are supported by the overhead

guard.

WARNING

Overhead guard must be in place to protect

operator from falling objects.

3. If the overhead guard shall be disassembled from the

fork lift truck for repair or replacement, make sure to

install the lifting hook to the overhead guard.

4. Remove the battery cover and control cover, and then

remove the floor. Disassemble all the kinds of wir-

ings from the overhead guard.

5. Remove the overhead guard mounting bolts.

6. Lift overhead guard from the truck

38-3-2 • Overhead Guard Removal and Installation

SM 765, Nov ’06

Group 38, Counterweight and Chassis

Operator's Seat Deck and Hood

! CAUTION

Removal and Installation

SAFE PARKING. Before working on truck:

1. Park truck on a hard, level and solid sur-

Removal

face, such as a concrete floor with no

gaps or breaks.

1. Push the hydraulic control lever bracket which locks

2. Put upright in vertical position and fully

the deck of operator's seat. Pull the handle on the

lower the forks or attachment.

right side of hydraulic control lever bracket and push

3. Put all controls in neutral. Turn key

the lever bracket forward, then the deck of operator's

switch OFF and remove key.

seat can be lifted.

4. Apply the park brake and block the

2. Remove the nuts holding the seat slide studs to the

wheels.

seat deck.

Floor Plate Removal and Installation

1. Tilt the steering column fully forward.

2. Fold the floor plate on its hinge and lift out the oper-

ator’s compartment. Rubber mat lifts out with floor

plate. Floor plate is not fastened to the truck.

3. To replace the floor plate, position the front of floor

plate first, then unfold it out into position.

Torque to :

6-13 N.m

(60-120 in-lb)

IMPORTANT

Make sure the accelerator pedal has a full

stroke and does not bind.

Torque to :

23-25 N.m

(203-221 in-lb)

3. The seat deck, which is held on the seat deck by the

seat mounting fasteners, may now also be removed.

38-4-2 • Floor Plate, Seat and Seat Deck Removal and Installation

SM 765, Nov ’06

Group 40, Specifications

Nameplate and Decals Locations

WARNING

BEFORE OPERATING lift truck, operator must:

• Be trained and authorized.

• Read and understand operator's

manual.

• Not operate a faulty lift truck.

• Not repair lift truck unless trained and authorized.

• Have the overhead guard and load backrest

extension in place.

DURING OPERATION, lift truck operator must:

• Wear a seat belt.

• Keep entire body inside truck cab.

• Never carry passengers or lift people.

• Keep truck away from people and obstructions.

• Travel with lift mechanism as low as possible.

and tilted back.

TO PARK lift truck, operator must:

• Completely lower forks or attachments.

• Shift into neutral.

• Turn off key.

• Set parking brake.

WARNING

Read the

manual

Buckle up!

Apply brake

when leaving

truck

Watch Out

For Other

People

Most lift truck

INJURIES

are to other

people near

the lift truck.

Prevent

Overturns!

AVOID :

slippery,

sloping,

or uneven

surfaces

loads over

capacity on

nameplate

• unstable or

high loads

• low tire

pressure

poorly

maintained

lift truck

fast or

sharp turns

In Case of

Tip-Over:

Don't

jump

Hold on

tight

Brace feet

Lean

away

! WARNING

Disconnect battery before handling

WARNING

electrical components.

Connect positine to positive, negative

to negative to prevent damage.

40-1-2 • Nameplate and Decals

SM 765, Nov ’06

Group 40, Specifications

on plate). Personal injury and damage to the truck

Nameplate and Decals

can occur if these capacities are exceeded.

This section shows the nameplate (data and capacity

5. Truck weight - The approximate weight of the truck

plate) and decals required to be on all operating Clark

without a load on the forks. The truck weight plus the

industrial trucks. The nameplate lists the data on the truck

weight of the load must be considered when operat-

- type and serial number - and the capacities of the truck.

ing on elevators, elevated floors, etc., to be sure it is

Decals depict or explain the hazards the operator must

safe.

avoid when operating the truck. The nameplate and decals

are placed in specific locations on the truck and are

intended to warn others working around the truck of its

CAUTION

hazards as well. The nameplate and decals MUST BE IN

Before attachments are added, or if the truck

PLACE on all trucks.

is modified after leaving the factory, you

If any decals or the nameplate are missing from the truck,

must contact your authorized Clark dealer

check with your local Clark dealer for replacements. This

for authorization and a new nameplate as

is required by OSHA.

capacity will be affected. This is required by

OSHA.

IMPORTANT

Do not allow a lift truck with damaged or

missing decals or data plate to be placed in

service. Replace them immediately. They

contain important information as described

on the following pages. This is required by

OSHA. The location of all decals is also

shown on the following pages.

Truck Data and Capacity Plate

The truck data and capacity plate provides essential infor-

mation about the truck. This information is important for

both operators and service personnel. Operators can see

what the truck’s capacities and load ratings are. Service

personnel must identify the truck model, type, and serial

number when ordering parts. Refer to numbers on exam-

ple data plate illustration.

1. Truck model number or registered name.

2. Truck serial number--An identification number

assigned to this particular truck and should be used

when requesting information or ordering service

parts for this truck from your authorized CLARK

dealer. The serial number is also stamped on the

frame.

3. Attachment description (if any installed)--The user

must see that the truck is marked to identify the

attachment(s), including weight of the truck/attach-

ment combination and truck capacity with the attach-

ment.

4. Capacity rating, load center, and lifting height data

Shows the maximum load capacity of this truck with

relation to load centers and fork heights (see diagram

SM 765, Nov ’06

Nameplate and Decals • 40-1-3

Group 40, Specifications

Warning Decal

Operator Safety Decar

The Operator Safety Warning Decal describes basic safe

The Operator Safety Decal depicts

WARNING

operating procedures that should be used when operating

impotant points about truck operation

Read the

the truck. This decal depicts important points about truck

and warns operators about truck safety

manual

operation and warns operators about truck safety hazards.

hazards. The Operator Safety Decal is

This decal is meant as a reminder for operators. It is

meant as a reminder for operators and is

placed where operators can review the points daily as they

placed where operators can review the

Buckle up!

conduct a visual inspection and prepare the truck for

points daily as they conduct a visual

work.

inspection and prepare the truck for

work.

Apply brake

when leaving

truck

Watch Out

WARNING

For Other

People

BEFORE OPERATING lift truck, operator must:

Be trained and authorized.

Read and understand operator's

manual.

Not operate a faulty lift truck.

Most lift truck

INJURIES

Not repair lift truck unless trained and authorized.

are to other

Have the overhead guard and load backrest

people near

extension in place.

the lift truck.

DURING OPERATION, lift truck operator must:

Prevent

Wear a seat belt.

Overturns!

Keep entire body inside truck cab.

Never carry passengers or lift people.

Keep truck away from people and obstructions.

Travel with lift mechanism as low as possible.

and tilted back.

AVOID :

slippery,

sloping,

TO PARK lift truck, operator must:

or uneven

Completely lower forks or attachments.

surfaces

Shift into neutral.

loads over

Turn off key.

capacity on

nameplate

Set parking brake.

Clark Material Handling Co.

Sit Down Rider

2798233

unstable or

high loads

low tire

pressure

IMPORTANT

poorly

maintained

Safety and warning decals are placed in con-

lift truck

spicuous locations on the truck to remind

fast or

sharp turns

operators of essential procedures or to pre-

vent them from making an error that could

In Case of

damage the truck or cause personal injury.

Tip-Over:

Safety and warning decals should be replaced

Don't

jump

immediately if missing, damaged or illegible.

This is required by OSHA.

Hold on

Lift trucks can be tipped over if operated improperly.

tight

Experience with lift truck accidents has shown that the

driver cannot react quickly enough to jump clear of the

Brace feet

truck and overhead guard as the truck tips. To protect

Lean

operators from severe injury or death in the event of a tip-

away

over, make sure this decal is in place to remind them to

always use their seat belts.

2798235

40-1-4 • Nameplate and Decals

SM 765, Nov ’06

Group 40, Specifications

Hand Safety Warning Decal

Battery Disconnect Warning Decal

This safety decal is placed on the upright to warn of the

This warning decal is located on the front of the seat deck.

danger of injury from movement between rails, chains,

It warns of the danger of truck movement when removing

sheaves, fork carriage, and other parts of the upright

or inserting the battery connector by calling for turning

assembly. Operators and others should never climb on or

the key switch to OFF and setting the parking brake.

reach into the upright. Personal injury will result if any

body part is put between moving parts of the upright.

! WARNING

Turn key switch off

and set parking

brake before

removing

or inserting battery

2791862

connector.

Truck may start in

Keep Away from Forks Decal

motion if you do not.

This safety decal is placed on the upright to warn of the

2743642

danger of injury from forks when they are in the raised

position. Operators and others should never ride on or

stand under forks or attachments. The forks can fall and

cause injury or death.

Polarity Warning Decal

This warning decal is located on the front of the seat deck,

adjacent to the Battery Disconnect Warning Decal. It

notes the need to disconnect the battery before handling

electrical components and to always make electrical con-

nections positivc to positive and negative to negative to

prevent damage.

WARNING

Disconnect battery before handling

electrical components.

Connect positive to positive, negative

to negative to prevent damage.

SM 765, Nov ’06

Nameplate and Decals • 40-1-5

Group 40, Specifications

Weights and Performance Specifications

Capacities

For standard trucks.

At 500 mm (24 in)

Models

Load Center

GEX 20

2000 kg 4000 lbs

GEX 25

2500 kg 5000 lbs

GEX 30

3000 kg 6000 lbs

Note: Rated capacity applies when using uprights with maximum fork height up to and including 3195 mm (126 in) For

GEX 20-30 .

Truck Weights and Axle Weights

Approximate weights for standard trucks with 126” Standard upright and GEX20/25 28.2”, GEX30 33.9” comportment.

Gross Vehicle

Empty Vehicle

Loaded Drive

Empty Drive

Empty Steer

Weight

Axle weight

kg(lbs)

GEX 20

6035(13305)

4035(8895)

5216(11499)

2088(4603)

819(1805)

GEX 25

6235(13745)

4235(9336)

6115(13481)

2133(4702)

620(1367)

GEX 30

6330(13955)

4330(9546)

6755(14892)

2178(4801)

575(1268)

Note: Refer to the truck data plate for exact service and axle weights.

Parking Brake Test

The brake must be capable of holding the truck with a full rated-capacity load on a 15 % grade.

Travel Speeds

Maximum speeds with standard upright for Standard Models.

80 Volt

GEX 20 no load

16.7kph (10.4mph)

GEX 25 no load

16.7kph (10.4mph)

GEX 30 no load

16.6kph (10.3mph)

GEX 20 with load

15.7kph (9.8mph)

GEX 25 with load

15.4kph (9.6mph)

GEX 30 with load

15.2kph (9.4mph)

Turning Radius

Battery Compartment : 716mm/28.2in

GEX20 : 1905mm/75.0in

GEX 25 : 1905mm/75.0in

Battery Compartment : 860mm/33.9in

GEX30 : 2000mm/78.7in

40-2-2 • General Specifications

SM 765, Sep ’06

Group 40, Specifications

Drift, Lift and Tilt Cylinders

Upright fork Downdrift: Should not exceed 100 mm (4 in) in a 10-minute period.

Tilt Cylinder Drift: Should not exceed 5° in a 10-minute period.

Determined by marking and measuring carriage descent and upright forward tilt from raised, non-tilted position with

hydraulic fluid at operating temperature: and a capacity load held evenly distributed on lift forks. (If a pallet is used, load

should not extend beyond pallet: load should be stacked to provide maximum stability). Fork completely engaging load

and adjusted as wide-as possible to provide even distribution of weight.

Lift and Lowering Speeds, Upright

Lift Loaded

Lower Loaded

Lift Empty

Lower Empry

m/s(fpm)

GEX 20 80V

Standard

0.48(94)

0.47(92)

0.54(106)

0.43(85)

Triple-Stage

0.47(92)

0.52(102)

0.43(85)

GEX 25 80V

Standard

0.41(81)

0.47(92)

0.54(106)

0.43(85)

Triple-Stage

0.45(89)

0.47(92)

0.52(102)

0.43(85)

GEX 30 80V

Standard

0.38(75)

0.47(92)

0.50(98)

0.43(85)

Triple-Stage

0.39(77)

0.47(92)

0.48(94)

0.43(85)

Critical Fastener Torque Specifications

For standard transaxle trucks.

Tightening Torque. Dry

N.m

ft-lb

Drive Axle-to-Frame Mounting Bolts:

450-500

332-369

Drive Wheel Lug Nuts

155-180

114-133

Steer Axle Mounting Bolts

240-265

180-196

Steer Wheel Lug Nuts

225-250

165-185

Steering Handwheel Retaining Nut

35-45

25.8-33.2

Tilt Cylinder Yoke Clamp Bolts

170-190

120-140

Tilt Cylinder Pin Retainer Bolts

Front

40-45

30-33

Rear

40-45

30-33

Counterweight Mounting Bolts (Bottom)

340-380

250-280

Brake System Specifications

Service Brake

Type: Wet disc brake

Fluid: Hydraulic fluid, RANDO HD32 or NUTO H32 in accordance with CLARK specification MS-68 (CLARK

#2776239)

Pedal Freeplay: None

Parking Brake

Type: Hand brake linked to service brake shoe at each wheel.

Holding Test: Rated load on 15% grade.

SM 765, Sep ’06

General Specifications • 40-2-3

Group 40, Specifications

Steering Column and Gear Specifications

Tilt Cylinders Specifications

Steering System Type: Hydrostatic power steeing.

Tilt cylinder type: double-acting with shims

Maximum Operating pressure: 21,000 kPa (3,045 psi; 210

Steering System Relief Pressure Setting: 10,000 kPa

bar)

(1450 psi)

Tilt Ranges

Steer Axle Specifications

(Abbrcviations - Std = Standard, high-visibility upright;

Steer Cylinder Type: Double-acting, piston-type.

TSU = Triple-stage upright HI-LO:Full Free lift upright;

MFH = maximum fork height: B = back tilt; F = forward

Lilt)

Hydraulic Sump, Filters, and Pump

MAST

BACK

FORWARD

MFH mm(in)

TYPE

"B"( ˚ )

"F"( ˚ )

Specifications

GEX

Hydraulic Pump Type: Integral gear type pump and motor

STD

2015(83)~3860(152)

assembly.

STD

4165(164)~4620(182)

Sump Type and Capacity: Removable tank mounted in

STD

5170(203.5)~

truck side frame with maximum capacity of 25 L (6.6 gal-

TSU

3860(152)~4800(189)

lons)

TSU

5210(199)~6100(240)

TSU

6370(251)~

Hydraulic Fluid Type: Clark Hydraulic Fluid specification

QUAD

ALL

MS-68.

Hydraulic Fluid Filters: Return line filter and suction line

Upright Specifications

screen mounted in sump.

Return Filter Type: Disposable, 25 micron, full flow.

Upright Weight: approximately 341 kg (753 lb) to approx-

imately 971 kg (2140 lb)

Suction Screen: 100 mesh stainless steel screen.

Carriage Weight: approximately 136 kg (300 lb)~150kg

(330 lb)

Hydraulic Valve/Lift Circuit Specifications

Fork Weight: approximately 50-62 kg each (110-137 lb)

Rated Flow: 75 L/min (20 gpm)

IMPORTANT

Before hoisting, the weights of upright, car-

Counterweight and Chassis Specifications

riage, and forks must be combined to deter-

mine what lifting capacity is required of the

Counterweight weights:

hoisting equipment.

Short wheel base

Long wheel base

Capacities and Lift Heights: Upright, carriage, and fork

28.2 BC

33.9 BC

capacity and upright lift heights are listed on the truck’s

data plate.

560 kg (1235 lbs)

GEX20

Lubricants:

760 kg (1675 lbs)

GEX25

All Purpose Grease (Clark specifications MS-9)

720 kg (1587 lbs)

GEX30

Innerslide Lubricant (Clark part #886396)

Chain and Cable Lube (Clark part #886399)

40-2-4 • General Specifications

SM 765, Sep ’06

Clark GEX20-30 (RATED CAPACITY : 2000~3000kg). SERVICE MANUAL (2006) - page 4