JCB 3CX, 4CX, 214e, 214, 215, 217 & VARIANTS Backhoe Loader. Service Manual

Section E

Hydraulics

Section E

24 - 2

Service Procedures

24 - 2

Test Cylinder/Piston Leakage

C Test Spool Leakage

Ensure that the oil temperature is at 50°C (122°F) by

Note: The following procedure applies only to services fitted

using the hydraulic oil temperature probe detailed in A1.

with A.R.V.'s. Note A.R.V.'s are not fitted to loader lift,

loader auxiliary, stabilisers or to the bucket rod side service

Take the weight off the ram to be tested, in this example,

except when a Rockbreaker is fitted.

by positioning the backhoe with dipper vertical and

bucket on the ground.

Render the A.R.V.'s inoperative in the suspect service.

Use a suitable pressure gauge A to blank off the

This is achieved by removing the A.R.V. and replacing

supporting port of the ram.

with a blanking plug (part no. 25/609901) and seal kit

(25/610301).

Disconnect the hose from the opposite port D and leave

the port open to atmosphere.

Re-check the piston rod movement as described steps

A1 to A6.

Apply a load to the suspect ram for example the boom

ram by raising the dipper to the horizontal as at B.

A.R.V.

Control Layout

After the initial movement measure the pin to pin

JCB ISO

movement as at C and note the rod movement over 10

minutes.

Slew

If rod movement is evident the ram is defective.

- Right

- Left

Boom

- Rod

- Head

Dipper

- Rod

- Head

Bucket

- Rod

- Head

Note: Bucket ram rod side ARV only fitted to machines

equipped with Rockbreakers.

If the rod movement is now acceptable the A.R.V. must

be at fault. The A.R.V. may only require cleaning and

then resealing. If dirt is evident, the hydraulic tank should

be drained and cleaned. It is recommended that when

re-filling the hydraulic tank that new oil and filter be used

to prevent further contamination. If the A.R.V. is worn it

should be replaced.

FIG 2

380200

380201

A401470

9803/3280

Issue 1

Section E

Hydraulics

Section E

24 - 3

Service Procedures

24 - 3

Table 1

Ram

Cylinder

Rod

Total Displacement - mm/10 minutes @

Dia. (mm)

69 bar

138 bar

207 bar

(1000 lb/in2)

(2000 lb/in2)

(3000 lb/in2)

HEAD SIDE

Backhoe

S/shift Jack Leg

Knuckle

100

Ext Dip

Loader

Clam

Lift

ROD SIDE

Backhoe

Boom

110

Boom

120

Boom

130

Boom

140

Bucket

114

Bucket

100

Dipper

100

Dipper

110

Ext Dip

Loader

Shovel

Using the figures above, a graph can be plotted and the maximum amount of movement determined. See the next page for a

working example.

9803/3280

Issue 1

Section E

Hydraulics

Section E

24 - 4

Service Procedures

24 - 4

EXAMPLE - Boom Ram110 x 60

Using the figures given in the table on page 3, plot a

graph for the ram to be tested.

Check the pressure in the ram (induced by the applied

load). In this example the pressure on the gauge reads

107 bar; 1500 lb/in².

Draw a vertical line from the pressure reading to the

plotted graph line. Where the vertical line intercepts the

graph line, draw a horizontal line and read the permitted

ram displacement. In this example the permitted

maximum displacement is 18 mm.

Note: A blank graph is provided on the next page,

photocopy and use as required.

120

100

52mm

26mm

18mm

8mm

100

150

200

250

69bar

107bar

138bar

207bar

PRESSURE (BAR)

380210

9803/3280

Issue 1

Section E

Hydraulics

Section E

25 - 1

Service Procedures

25 - 1

Quick Release Couplings

- Connecting and Disconnecting

! WARNING

Flat face quick release couplings allow the operator to

Hydraulic fluid at pressure can injure you. Make the

remove and install attachments swiftly and efficiently.

machine safe before connecting or disconnecting quick

Generally, your machine pipework will have female couplings

release couplings; stop the engine and then operate the

A fitted, and the optional attachment hoses will have male

attachment control a few times to vent residual hydraulic

couplings B fitted.

pressure in the attachment hoses.

2-4-1-11

The quick release couplings should be trouble free and

relatively easy to connect and disconnect, provided they are

Before connecting or removing any hydraulic hose, residual

kept clean and used correctly. The recommendations listed

hydraulic pressure trapped in the service hose line must be

below should always apply when using flat face quick

vented. This is usually achieved by switching off the engine

release couplings.

and then operating the attachment control lever several

times. Make sure the hose service line has been vented

Finally, please read the correct fitting and releasing

before connecting or removing hoses - refer to the

procedures before installing or removing any optional

appropriate attachment information in this section.

attachment fitted with quick release couplings.

Quick Release Couplings - Do's & Don'ts

Connecting Quick Release Couplings

Remove any residual hydraulic pressure trapped in the

DO wipe the two faces of the coupling and make sure they

service line hose.

are clean before connecting.

Wipe the two faces of the male and female couplings

DO make sure the outside sleeve (female coupling) is pulled

and make sure they are clean.

back when disconnecting.

Make sure that ball C in the female coupling is located

in one of its slots.

DO connect and disconnect a new coupling two or three

times to 'work' the PTFE seals - sometimes a new coupling

Fit the male coupling into the female coupling; To

will stick if the seals have not been 'worked'.

ensure that the coupling is not accidentally released,

rotate sleeve E half a turn and make sure that the

DO use a spanner on the hexagon flats of the coupling when

locking ball C does not align with the slot D.

fitting adaptors.

DO use a rubber or hide hammer to disconnect a coupling if

Disconnecting Quick Release Couplings

it sticks - sticking may occur if there is dirt present in the

coupling.

Remove any residual hydraulic pressure trapped in the

service line hose.

DON'T attempt to re-connect a damaged half coupling - this

Align the slot D with ball C.

will destroy the seals and necessitate replacing both half

couplings.

Pull back sleeve E to release the coupling.

DON'T leave the coupling where it may be run over by a

machine or otherwise crushed - this will distort the coupling

sleeve and prevent correct connection and disconnection.

DON'T clamp on the smooth diameter of the coupling when

fitting adaptors - always use the hexagon.

DON'T try to turn the sleeve (female coupling) when the

coupling has been disconnected - the locking ball will wedge

underneath the sleeve and destroy the coupling.

DON'T damage the faces of the couplings - this can prevent

connection and disconnection, or damage seals and cause

leakage.

DON'T try to dismantle the couplings - they are non

serviceable parts. If a coupling is damaged it should be

replaced with a new one.

S169490

9803/3280

Issue 1

Section E

Hydraulics

Section E

26 - 1

Service Procedures

26 - 1

Smooth Ride System

Charging/Discharging the Accumulator

Discharging

Charging

Park the machine on level ground, lower the loader

arms, switch off the engine and chock all four wheels.

Release all hydraulic pressure in the accumulator by

selecting the starter key to the ON position without the

engine running, SRS ON and operating the loader arm

hydraulic lever.

Remove gas valve guard A and gas valve cap B.

Screw T handle C all the way out (counter clockwise)

before attaching charging tool (service tool 892/00948)

to accumulator gas valve.

Close bleed valve D.

Either connect charging tool to a bottle of compressed

Making sure not to loop or twist the hose, connect the

nitrogen gas which is turned off or remove hose F and

charging tool to the gas valve. Tighten to 1.0 lbf ft (1.36

fit a suitable blank on charging tool.

Nm, 0.14 kgf m).

Screw T handle C all the way in (clockwise), this will

Connect charging tool to a bottle of compressed

depress the core in the gas valve.

nitrogen gas.

Open bleed valve D until all the gas charge is relieved

Screw T handle C all the way in (clockwise), this will

from the accumulator. Remove the charging tool.

depress the core in the gas valve. Check charge

pressure which should be set to suit the loader and the

attachment fitted to the machine. For recommended

charge pressures refer to Technical Data - Smooth

Ride System.

If charge pressure is low, carefully open hand valve E

on the nitrogen bottle and SLOWLY fill the accumulator.

Close valve E when the required charge pressure is

reached on the gauge.

Let the pressure settle for 10 to 15 minutes. This will

allow the gas temperature to stabilise. If the charge

pressure is exceeded, with the gas bottle closed, open

bleed valve D. Reduce pressure as required, then close

bleed valve.

! CAUTION

To reduce pressure use the recommended charging tool

or the charge valve could be damaged which may result

in rapid discharge of the accumulator.

HYD 2-4

When complete screw T handle C all the way out

(counter clockwise) then open the bled valve D to vent

the hose.

Hold the gas valve to keep from turning, loosen nut and

remove charging tool.

Refit gas valve cap and valve guard.

S308270

9803/3280

Issue 1

Section E

Hydraulics

Section E

27 - 1

Service Procedures

27 - 1

Hose Burst Protection Valves

The hose burst protection valves (if fitted) prevent the loader

or backhoe falling in the event of a hose burst. These valves

may be fitted on rams which raise or lower the loader arms,

the boom or the dipper.

Lowering a Load - In a Failure Condition

Checking

During normal operation, the engine must be running before

Raise the loader arms fully. Raise the boom to about

a load can be lowered. The following paragraphs describe

45°. Raise the dipper to the horizontal.

how to safely and correctly lower a load in the event of

engine failure or a hose burst; we recommend that only a

Stop the engine

competent maintenance engineer perform the procedures.

Using the control levers, try to lower the loader, boom

After lowering a load do not use the machine until the

and dipper. Push the levers fully to the 'lower' position.

manual over-ride screw has been reset (Loader HBPV, refer

If there is any movement, adjust or replace the hose

to Pressure Testing - Loader Lift Ram) or a new end cap

burst protection valve as applicable.

and valve assembly fitted (Boom HBPV, refer to Hose Burst

Protection Valves - Dismantling and Assembly), otherwise

the valve will not operate as intended.

S320930

! DANGER

Do not stand underneath the raised load during the

lowering procedure. Stand clear and to one side until the

load has been safely lowered. Make sure that the area is

clear of other people before lowering the load. If you do

not follow these precautions you or others could be

killed or seriously injured.

2-3-5-3

Boom and Dipper Hose Burst Protection Valve (HBPV)

Remove cap A and pierce the warning label.

S170582

If a hose has burst, position a suitable container to

catch the oil.

Insert an 6mm allen key into the socket head of screw

B. Slowly turn the allen key in a clockwise direction until

the load just begins move.

Burst hose - Lower the boom using screw B, turn the

screw counter-clockwise to slow or stop the load from

lowering.

Dead engine - Operate the control lever in the cab to

lower the load.

Loader Hose Burst Protection Valve (HBPV)

Remove cap C from both HCPV check valves on the

A171340

loader lift arms.

If a hose has burst, position a suitable container to

catch the oil.

On the burst hose HBPV, insert an 5mm allen key into

the socket head of screw D. Turn the allen key in a

clockwise direction so that the screw winds fully in.

Repeat slowly for the opposite side as the load is now

supported on this HBPV.

Note: Count the number of full turns on each screw for

resetting purposes.

Operate the control lever in the cab to lower the load.

9803/3280

Issue 1

Section E

Hydraulics

Section E

27 - 2

Service Procedures

27 - 2

Hose Burst Protection Valves

Pressure Testing - Loader Lift Ram

The following text describes the pilot valve setting

procedures and pressure testing sequences for ONE HBPV

only, repeat the procedures for BOTH loader arm lift rams.

Preparation

Pilot Valve Setting Procedure

Before starting the pressure testing procedure vent hydraulic

The pilot valve assembly, shown at C, must be set correctly

system pressure as follows:

before doing the relief valve pressure test. If the pilot valve

is screwed too far into the HBPV it will create a flow path

Park the machine on firm level ground, engage the

connection from port C2 to port V2 (see descriptions of

parking brake and set the transmission to neutral.

operation).

Lower the loader arms to the ground (not lifting the

To set the pilot valve assembly:

machine).

Remove pilot housing, item D, from the HBPV.

Select 'ARMS LOWER' to raise the front wheels

approximately 25 - 50 mm (1 - 2 in) off the ground.

Check that the end face of the pilot valve assembly,

item C, is flush (level) with the end face of its housing

Switch off the engine.

D, as shown at E.

Make sure all personnel are clear of the machine before

If necessary, remove end cap F and, using a suitable

completing step 6.

Allen key, adjust the pilot valve as required.

Select 'ARMS RAISE' - this will vent residual hydraulic

Refit the end cap.

pressure from the loader rams (head side).

Continured

Move all the backhoe control levers back and forth to

vent any other residual hydraulic pressure from the

backhoe service hoses.

327330

9803/3280

Issue 1

Section E

Hydraulics

Section E

27 - 3

Service Procedures

27 - 3

Hose Burst Protection Valves

Pressure Testing - Loader Lift Ram

(continued)

Relief Valve Pressure Test

If the hose burst protection valve has been stripped and

cleaned, then pre-set the valve as detailed in step 1. The

pressure test procedure is described in steps 2 to 6.

Pre-set the relief valve:

a Remove cap B and its copper washer. Using an

Allen key, turn the adjusting screw anti-clockwise

to remove all tension.

b Using your fingers, turn the adjusting screw

clockwise until a soft force (resistance) is felt.

c Using an Allen key, turn the adjusting screw a

further 21/4 turns to pre-set the relief valve. Refit

the cap and washer.

Remove hose G from port C2. Cap and plug the hose

and valve port adapter (the valve port adapter MUST be

plugged, otherwise the test procedure will not work).

Remove hose J from port V2. Plug the hose but DO

NOT cap the valve port adapter.

Remove plug A and in its place fit a 0-400 bar (0-6000

lbf/in²) pressure gauge connected to a hand pump.

Use the hand pump to increase the pressure. When the

pressure reaches the setting of the relief valve, oil will

escape from port V2, shown at K. Note the maximum

gauge reading (the setting of the hose burst relief valve)

which should be 250 bar (3625 lbf/in²).

If necessary, adjust the pressure setting as follows:

a Remove cap B and its copper washer.

b Using an Allen key, turn the adjusting screw

clockwise to increase the pressure or anti-

clockwise to decrease the pressure. For

information; one full turn of the relief valve adjusting

screw is equivalent to approximately 110 bar (1595

lbf/in²).

c Replace the cap and washer.

d Repeat pressure test, adjust as necessary.

9803/3280

Issue 1

Section E

Hydraulics

Section E

30 - 1

Main Pump

30 - 1

Fixed Flow

Replacement

Replacement is the reverse of the removal procedure.

Removal and Replacement

Clean off all traces of gasket compound from the pump

The following Procedure describes removal and replacement

and gearbox mounting faces. Apply a thin bead of JCB

of a double section pump, follow the same procedure for

Multigasket to the gearbox mounting face.

single section pumps.

Locate the splined shaft of the pump into the gearbox.

Removal

Apply JCB Threadlocker and Sealer to bolts E and

secure the pump flange to the gearbox mounting face.

! WARNING

Reconnect the pump outlet hoses C and D to the

Make the machine safe before getting beneath it. Ensure

elbow fittings.

that any fitments on the machine are secure; engage the

parking brake, remove the starter key, disconnect the

Note: All hydraulic adapters that are installed together with

battery.

a bonded sealing washer must also have sealant JCB

INT-3-3-8

Threadseal applied to the threads of the adapter.

Remove the propshaft, refer to Section F Propshafts -

Reconnect the pump inlet hose flange to the pump

Removal and Replacement.

body with bolts B (4 off).

Drain the hydraulic fluid from the hydraulic tank.

Fit the propshaft, refer to Section F Propshafts -

Removal and Replacement.

Remove flange bolts B (4 off) and disconnect the pump

inlet hose flange from the pump body. Blank off all

Fill the system to the correct level with recommended

exposed connections to prevent ingress of dirt.

hydraulic fluid, refer to Section 3 Fluids, Lubricants,

Capacities and Specifications.

Disconnect the pump outlet hoses C and D from the

elbow fittings. Blank off all exposed connections to

Note: Replace the suction strainer and return line filter after

prevent ingress of dirt.

fitting a new or serviced pump.

! CAUTION

After fitting a new or serviced pump and before starting

The hydraulic pump is heavy. Do not attempt to remove

the engine screw the main relief valve out. Run the

the pump unless its weight is held by a sling. Make sure

engine and check for leaks, also check the main relief

that the sling is attached to a suitable lifting appliance.

valve (M.R.V.) operating pressure. Refer to Section E

HYD 2-3

Service Procedures, Pressure Testing - MRV.

Secure the pump using a sling around the pump body,

remove the pump mounting bolts E and carefully

withdraw the pump clear of the gearbox.

Torque Settings

Item

kgf m

lbf ft

TBA

A396190

9803/3280

Issue 1

Section E

Hydraulics

Section E

31 - 2

Main Pump

31 - 2

Fixed Flow

Dismantling and Assembly

Discard O-ring 31.

Before removing and dismantling the pump, check flow and

pressure. If either of these are low the pump must be

Remove all sealant from the contact faces of the

changed. Renewal of components such as gears, bearings

mounting flange/front body and end cover/rear body

and housing will not effect a permanent cure. If the pump

interfaces.

output is satisfactory but there is external leakage, the pump

should be removed and dismantled for re-sealing only.

Wash all components and immediately apply a coating

of hydraulic oil to prevent corrosion.

Before removing and dismantling the pump, make sure the

exterior of the pump and working area is thoroughly cleaned

Inspection

and free of possible sources of contamination.

Generally check all pump parts for damage and/or

Dismantling

wear. The O-ring grooves, the seal recess in the

mounting flange and all sealing faces must be free of

Remove the four bolts 3 and serrated washers 4 which

burrs and scores which could result in seal damage

clamp the units together.

and hence hydraulic oil leakage.

Use a soft faced hammer to separate front body 5 and

Renew the pump if any of the following symptoms

rear body 6 after first marking them to ensure correct

exist:

re-assembly.

The PTFE coated bearings in the pump bodies, the

Remove splined coupling 7 and O-rings 8. Discard the

mounting flange and the end cover are worn

O-rings.

through to reveal the bronze backing.

Use a soft faced hammer to separate end cover 9 from

The gear side faces are scored. Often

rear body 6, after first marking them to ensure correct

contaminated fluid results in a distinct wear step

re-assembly.

coincident with the gear root diameter. This can

normally be felt by drawing a sharp point across

Remove drive gear 10 from its bore. Pushing it out of

the gear side face from the journal towards the tip

the rear body will also remove balance plate 11

of the gear.

complete with seal 12 and seal energiser 13. Discard

the seal and seal energiser. Note the position of the

There is a noticeable wear groove on driveshaft 23

driveshaft and the balance plate to ensure correct re-

where seals 22 run.

assembly.

The balance plate faces are scored, particularly in

Remove driven gear 14, followed by balance plate 15

the area adjacent to the gear root diameter.

complete with seal 16 and seal energiser 17. Discard

the seal and seal energiser.

The shaft splines are worn or severely fretted.

Discard O-ring 18.

The gear "cut-in" area in the low pressure side of

the pump body is deeper than 0.15 mm (0.006 in)

Use a soft hammer to separate mounting flange 19 from

or has a torn or pitted appearance.

front body 5, after first marking them to ensure correct

re-assembly.

Remove circlip 21 and shaft seals 22. Note which way

round the seal lips are fitted to ensure correct fitting of

new seals on re-assembly.

Remove driveshaft 23 from front body 5. Removal will

also remove balance plate 28 complete with seal 29 and

seal energiser 30. Discard the seal and seal energiser.

Remove driven gear 27 followed by balance plate 24,

seal 25 and seal energiser 26. Discard the seal and seal

energiser.

9803/3280

Issue 1

Section E

Hydraulics

Section E

31 - 4

Main Pump

31 - 4

Fixed Flow

Dismantling and Assembly (continued)

Fit balance plate 11 in its original position (i.e. with the

Assembling

two small holes to the low pressure side). Fit seal 12

and seal energiser 13 into the balance plate.

When carrying out the following procedure, renew all seals

and O-rings. Lubricate using JCB Special Hydraulic Fluid.

Fit O-ring 18 into end cover 9.

Fit shaft seals 22 into mounting flange 19, making sure

Apply a small amount of JCB Multigasket to the

the seal lips are the correct way round as noted in

exposed face of rear body 6 (i.e. the face containing

dismantling. Fit circlip 21 into its groove in the flange.

the clamping bolt holes).

Coat the seal lips with high melting point grease.

Fit end cover 9 in its original position, as marked

Note: If the seal recess is scored, it is permissible to seal

earlier.

outside diameter with JCB Multigasket to prevent leakage.

Install the four bolts 3, each with a serrated washer 4,

Stand front body 5 on its rear face. Fit seal 25 and seal

and tighten evenly and progressively to a torque of 90 -

energiser 26 into balance plate 24.

100 Nm (66 - 74 lbf ft).

Ensuring that the seals do not fall out, carefully feed the

Pour a small amount of clean JCB Special Hydraulic

balance plate into the bores of the front body 5 with the

Fluid into the ports. Check that driveshaft 23 rotates

two small holes through the balance plate to the low

without undue force. If excessive force is required it is

pressure side of the body (i.e. side with the large 4-bolt

possible that one or more of the balance plate seals are

port pattern).

trapped, in which case it will be necessary to dismantle

and assemble the pump again.

Insert driveshaft 23 and driven gear 27 into the original

bores.

Fit balance plate 28 over the driveshaft and gear stub.

Insert seal 29 and seal energiser 30 into the balance

plate.

Fit O-ring 31 into the groove on mounting flange 19.

Apply a small amount of JCB Multigasket to the face of

front body 5 which seals with mounting flange 19 (i.e.

the face containing the clamping bolt holes).

Carefully feed mounting flange 19 over driveshaft 23 in

its original position, as marked earlier. Use a soft faced

hammer to tap the flange onto its location spigot.

Support the front pump assembly on the mounting

flange (but not the driveshaft). Fit O-rings 8 into the

grooves on the rear face of the front body 5. Install

splined coupling 7.

Fit rear body 6 onto front body 5 in its original position,

as marked earlier, ensuring that it locates on the dowels

and that the clamping bolt holes line up.

Fit seal 16 and seal energiser 17 into balance plate 15.

Ensuring that the seals do not fall out, carefully feed the

balance plate into rear body 6 with the two small holes

through the balance plate to the low pressure side (i.e.

side without a port).

Fit drive gear 10 so that it locates with splined coupling

7. Fit driven gear 14.

9803/3280

Issue 1

Section E

Hydraulics

Section E

35 - 2

Main Pump

35 - 2

Variable Flow

Inspecting Parts

Generally check all pump parts for damage and/or wear. Any

Dismantling and Assembly

parts that are scored or damaged must be replaced with new

ones.

Before removing and dismantling the pump, make sure it is

the pump that is at fault. Complete all the necessary checks

The shaft ‘O’ ring grooves and all sealing faces must be free

as detailed in Service Procedures, Variable Flow Pumps.

of burrs and scores. During assembly, make sure that the

Make sure that the exterior of the pump and working area is

rotary piston group move freely. Renew all ‘O’ rings and

thoroughly cleaned and free of possible sources of

seals.

contamination. Following removal of the pump from the

machine, transfer it to a clean dirt free environment ready for

Assembly

dismantling.

Assembly is generally a reversal of the dismantle procedure,

The variable displacement pump has matched-ground

but note the following:

components. For this reason, some items will only be

available as a sub-assembly, for instance the barrel and

The taper roller bearing must have a preload of 0.0 to

piston assembly.

0.05mm (0.0 to 0.002in.). If the original bearing and shim is

being fitted no preload adjustment is required. If a new

All the ‘O’ rings, seals and bearings are available in a kit form

bearing is installed a preload adjustment is required:

from your JCB Distributor.

Preload Adjustment:

Dismantling

Install a setting shim of known thickness (as shown at

Refer also to Service Procedures, Variable Flow Pumps -

A). The shim thickness must be manufactured to a

Renewing Drive Shaft Seal.

tolerance of ± 0.01mm (0.0004in.). In this example the

shim thickness is 1.5mm.

Remove capscrews 1 (4 off) and detach the regulator

assembly 2 from the pump housing.

Fit the port plate item 3 and finger tighten the socket

screws. It is important that the socket screws are

Mark the position of the port plate 3 to pump housing 4.

tightened evenly and the port plate sits square.

Remove socket screws 5, and remove the port plate

Using feeler gauges measure the gap B between the

together with the valve plate 6, control piston 7 and

port plate and the pump housing 4. Measure in more

stroking piston 8. Hold the plate in position during

than one position to establish the port plate is fitted

removal.

evenly. Obtain shim thickness (dimensions in mm):

Remove taper roller bearing 9 and shim 10 from the

Example measured gap

1.26

drive shaft 11.

Subtract preload

- 0.05

Remove the rotary piston assembly 12 from the pump

Total

1.21

housing. Assembly includes shaft 11, bearing 15, and

cradle 16.

Known shim thickness

1.50

Subtract calculated preload

-1.21

Remove and discard port plate to pump housing ‘O’

ring 13.

SHIM THICKNESS

0.29

Remove bearing shells 14 and disc 17.

When the shim thickness has been calculated, remove the

setting shim A and fit the required shim (in this instance the

Remove the outer bearing races (not shown) from the

shim would be 0.29mm).

pump housing and the port plate. Only remove the

races if they are damaged and unserviceable.

Note: Setting shim A is not currently available as a service

tool. The shim (and the calculated shim) can be

Lift the valve plate 6 off the port plate, do not lose the

manufactured locally. Maintain a tolerance of ± 0.01mm

dowel pins (not shown).

(0.0004in.).

Remove and discard ‘O’ rings 18.

The lubrication bore relief (item C) on the cradle must be

fitted on the pressure side of the pump.

Remove control piston 7. Note that the control piston is

mounted on the same side as the regulator valve.

Check the control piston and the stroking piston move

smoothly.

Remove the stroking piston assembly 8.

The regulator valve assembly is currently a non serviceable

Further dismantling and assembly of the pump is not

part.

recommended.

9803/3280

Issue 1

Section E

Hydraulics

Section E

50 - 1

Loader Valve - Fixed Flow

50 - 1

Removal and Replacement

Manual Control

! WARNING

Disconnect all hydraulic hoses from the valve block

Make the machine safe before working underneath it.

and plug all orifices to prevent ingress of dirt. Label

Park the machine on level ground, lower the arms. Apply

each hose before disconnecting, this will ensure

the parking brake, put the transmission in neutral and

correct position when refitting.

stop the engine. Chock both sides of all four wheels.

Uncouple the dump solenoid electrical connector G.

Disconnect the battery, to prevent the engine being

Uncouple the electric detent connector H (if fitted).

started while you are beneath the machine.

GEN-1-2

Loosen and remove the three fixing nuts J. Remove the

! DANGER

loader valve and spacing washers C.

Hydraulic fluid at system pressure can injure you. Before

Replacement

disconnecting or connecting hydraulic hoses, stop the

engine and operate the controls to release pressure

Replacement is a reversal of the removal sequence.

trapped in the hoses. Make sure the engine cannot be

started while the hoses are open.

INT-3-1-11/1

! WARNING

Fine jets of hydraulic fluid at high pressure can

Removal

penetrate the skin. Do not use your fingers to check for

hydraulic fluid leaks. Do not put your face close to

* Note: The illustration shows a valve fitted with a bolt on

suspected leaks. Hold a piece of cardboard close to

auxilary spool 1. This item is only fitted to some machines,

suspected leaks and then inspect the cardboard for

typically Precision Control machines with extending dipper.

signs of hydraulic fluid. If hydraulic fluid penetrates your

skin, get medical help immediately.

Operate the valve block levers back and forth to vent

INT-3-1-10/1

residual pressure. On Precision Control machines also

operate the extending dipper foot pedal (if fitted).

After replacement check the main relief valve (M.R.V.) and

auxiliary relief valve (A.R.V.) pressure settings.

Remove clevis pins A and nuts B to disconnect the

control levers from the valve block spools. Disconnect

Note: All hydraulic adapters that are installed together with

the control cable D (if fitted). Undo the lock nut E. Undo

a bonded sealing washer must also have JCB Threadseal

the housing fixing screws and slide it down the cable.

applied to the threads of the adapter.

Remove the pin F.

A402470

9803/3280

Issue 2*

Section E

Hydraulics

Section E

50 - 7

Loader Valve - Fixed Flow

50 - 7

Dismantling and Assembly

Main Relief Valve (MRV)

Assembly

The numerical sequence shown on the illustration is intended

as a guide to dismantling.

Renew all 'O' rings and back-up rings.

For assembly the sequence should be reversed.

Lubricate parts with JCB Hydraulic Fluid before assembling.

Make sure that all the parts move freely.

The following points MUST be avoided when dismantling

and assembling the valve:

Make sure that the 'O' rings and back-up rings are fitted the

•

CONTAMINATION

correct way, items 10 and 11.

•

DAMAGE TO SPOOL

•

DAMAGE TO SEAL GROOVES

Adjust pressure setting as required, refer to Service

Procedures, Loader Valve - Pressure Testing.

All or any of the above points may result in possible

problems with the valve.

Torque Settings

Dismantling

Item

kgf m

lbf ft

When removing 'O' rings and seals, use an appropriately

5.4

0.6

rounded tool that WILL NOT cause any damage to the seal

grooves.

Discard ALL 'O' rings and back up rings. DO NOT use worn

or damaged items.

Inspect the valve components for scratches, nicks or any

other type of damage, replace with new if required.

9803/3280

Issue 1

Section E

Hydraulics

Section E

50 - 9

Loader Valve - Fixed Flow

50 - 9

Dismantling and Assembly

Auxiliary Relief Valves (ARV) and

Assembly

Load Hold Check Valves (LHCV)

Renew all 'O' rings and back-up rings.

The numerical sequence shown on the illustration is intended

as a guide to dismantling.

Lubricate parts with JCB Hydraulic Fluid before assembling.

Make sure that all the parts move freely.

For assembly the sequence should be reversed.

Fit back-up ring 13 on the upper side of 'O' ring 12.

The following points MUST be avoided when dismantling

and assembling the valve:

Fit flat face of sleeve 9 against shoulder of poppet 10.

•

CONTAMINATION

Torque tighten item 14 using the special tool (see Service

•

DAMAGE TO SPOOL

Tools), until its shoulder seats firmly against item 1.

•

DAMAGE TO SEAL GROOVES

All or any of the above points may result in possible

Pressure test the relief valves, refer to Service Procedures,

problems with the valve.

Loader Valve - Pressure Testing.

The ARV's are identical in design but have different pressure

Torque Settings

settings, refer to Technical Data.

Item

kgf m

lbf ft

The LHCV's are identical.

6.6

2.5

Dismantling

8.3

When removing 'O' rings and seals, use an an appropriately

rounded tool that WILL NOT cause any damage to the seal

grooves.

Discard ALL 'O' rings and back up rings. DO NOT use worn

or damaged items.

Dismantle sub-assembly 14 from item 1 using a special tool

(see Service Tools). The special spanner locates in cross

holes B.

Make sure that small drilling A is not blocked.

Ensure good condition of seating faces on poppet 18 and on

the mating face of the valve block.

Inspect the valve components for scratches, nicks or any

other type of damage, replace with new if required.

9803/3280

Issue 1

Section E

Hydraulics

Section E

50 - 11

Loader Valve - Fixed Flow

50 - 11

Dismantling and Assembly

Unloader Valve

Assembly

The numerical sequence shown on the illustration is intended

Renew all 'O' rings and back-up rings.

as a guide to dismantling.

For assembly the sequence should be reversed.

Lubricate parts with JCB Hydraulic Fluid before assembling.

Make sure that all the parts move freely.

The following points MUST be avoided when dismantling

Ensure that the small drilling through the centre of items 23,

and assembling the valve:

is clear.

•

CONTAMINATION

•

DAMAGE TO SPOOL

Shims 21 are intended to limit the maximum pressure

•

DAMAGE TO SEAL GROOVES

setting, the specified pressure setting is achieved by

adjusting capnut 15. If the specified pressure cannot be

All or any of the above points may result in possible

achieved under test, it is permissible to add shims as

problems with the valve.

required. There MUST be at least one hardened shim next

to the spring item 22.

Dismantling

Do not over-tighten the solenoid assembly, it may effect the

When removing 'O' rings and seals, use an an appropriately

operation of the solenoid, use the spanner flats and torque

rounded tool that WILL NOT cause any damage to the seal

tighten to figure indicated in the table below (items 1 and 5).

grooves.

Fit chamfered end of spring 22 against head of pilot poppet

Discard ALL 'O' rings and back up rings. DO NOT use worn

item 23.

or damaged items.

Check pressure setting after refitting, refer to Service

Use a nylon rod to push out spool assembly item 23, DO

Procedures, Loader Valve - Pressure Testing.

NOT damage spool bore.

Check the operation of the hydraulic speed control, refer to

Inspect the valve components for scratches, nicks or any

Service Procedures, Loader Valve - Pressure Testing.

other type of damage, replace with new if required.

Torque Settings

Item

kgf m

lbf ft

6.7

0.7

2.8

8.3

4.6

3.5

9803/3280

Issue 1

Section E

Hydraulics

Section E

50 - 13

Loader Valve - Fixed Flow

50 - 13

Dismantling and Assembly

Standard Spool - Manual

Assembly

The numerical sequence shown on the illustration is intended

as a guide to dismantling.

Fit the boot 1A to the seal plate 2.

For assembly the sequence should be reversed.

Fit a new lipseal 4 into the valve block, ensure square.

Fit wiper 3 on top of lipseal.

The following points MUST be avoided when dismantling

Fit the seal plate and boot assembly to valve block

and assembling the valve:

section but do not torque tighten capscrews 1 at this

•

CONTAMINATION

stage. Ensure wiper locates into seal plate.

•

DAMAGE TO SPOOL

Use clean hydraulic oil as a lubricant. From the bottom,

•

DAMAGE TO SEAL GROOVES

insert spool through the valve block, do not use

All or any of the above points may result in possible

excessive force when fitting, a turning motion should

problems with the valve.

ease the spool through the valve block.

Check that the tang end of the spool passes through

Dismantling

the boot without dislodging or damaging the boot.

Remove the lever linkage from the tang (lever) end of the

Ensure that the tang aligns with the control rod and

that the boot is not distorted and is located in the spool

spool.

land.

When removing 'O' rings and seals, use an appropriately

Torque tighten cap screws 1.

rounded tool that WILL NOT cause any damage to the spool

or seal grooves, for instance, item 3, which is a wiper seal

When fitting bolt 9, clean the threads thoroughly using

and is a press fit in the counterbore.

JCB Cleaner/Degreaser, leave it for 10 minutes then

apply a small quantity of JCB Threadlocker and Sealer

Care must be taken to ensure that the spool 8 is not

to the threads of the spool.

damaged when removing it from the valve block.

Make sure that all the parts move freely, check that

Hold the spool in clamp 992/10100, unscrew bolt 9 and

item 10 does not interfere with item 13.

remove spring 12, spacer 10 and cups 11 and 13.

Renew 'O' ring15. Make sure the 'O' ring is not trapped

Check for surface contamination on the under side of the

or damaged.

seal plates 2 and 14. Clean if necessary. Check for the

flatness of the seal plate. If found to be bent - replace with

Fit seal 15 and seal plate 14 to the valve block section.

new (any work previously carried out on this valve may have

Torque tighten capscrew 5 on completion.

resulted in the bending of the seal plate).

Re-connect the lever mechanism to the tang (lever) end of

the spool.

Run the engine and inspect the valve for external leaks.

Torque Settings

Item

kgf m

lbf ft

9.5

0.96

9.5

0.96

9.5

0.96

9803/3280

Issue 1

JCB 3CX, 4CX, 214e, 214, 215, 217 & VARIANTS Backhoe Loader. Service Manual - page 17