Freightliner Business Class M2. Manual - part 15

31–00 Safety Precautions

Safety Precautions in this section apply to all
procedures within this group.

DANGER

When working on the vehicle, shut down the en-
gine, set the parking brake, and chock the tires.
Before working under the vehicle, always place
jack stands under the frame rails to ensure the
vehicle can not drop. Failure to follow these steps
could result in serious personal injury or death.

31–01 Frame Fastener Torque

Check

Frame brackets and components secured with Huck-
bolt® fasteners do not require a torque check, how-
ever, they should be inspected for damage. Frame
brackets and components secured with conventional
bolts and nuts are to be checked at Initial Mainte-
nance (IM). Check the torque of frame fasteners to
offset the effects of "bedding in" (or seating). When
checking torque, torque the nut, not the bolt head
whenever possible. This will give a true torque read-
ing by eliminating bolt-body friction. When checking
the torque of frame fasteners, inspect the frame for
cracks and other damage. Set a click-type torque
wrench to the maximum torque of the fastener you
are checking. Apply pressure until the torque wrench
clicks. Do not loosen the bolt to check the torque.
Refer to Group 00 of the vehicle Workshop Manual
for torque specifications.

NOTICE

Make sure frame fasteners are properly tightened.
Continued vehicle operation with loose fasteners
could result in bracket or frame damage.

Check the fasteners at the following locations:

• Axle Stops
• Deck Plates
• Equalizer Brackets
• Exhaust Brackets
• Fifth Wheel Legs
• Fifth Wheel Mountings

• Frame Crossmembers and Gussets
• Front Frame Brackets
• Front Suspension Spring Brackets
• Fuel Tank Brackets
• Radius Rods
• Rear Suspension Spring Brackets
• Shock Absorbers
• All Other Frame Fasteners

Any component that shows signs of cracking or other
damage must be repaired or replaced. Refer to the
vehicle vehicle Workshop Manual for repair or re-
placement information.

31–02 Fifth Wheel Inspecting

WARNING

All fifth wheel maintenance, adjustment, and re-
building must be done only by a qualified me-
chanic. Improper or incomplete procedures could
result in a possible disengagement of the trailer
from the tractor, which could result in personal
injury or property damage.

Parts are under spring compression. Wear safety
goggles while servicing the fifth wheel. Failure to
do so can result in personal injury, due to parts
ejecting with force.

Fontaine

Using a degreaser, clean the fifth wheel and
mounting brackets.

Inspect for cracks in the fifth wheel assembly, the
mounting brackets, and mounting components.

Inspect for wear and damage to moving parts.

Check for loose nuts and bolts in the fifth wheel
and mounting hardware. Tighten nuts and bolts
as necessary.

Check the wedge adjustment.

5.1

Close the fifth wheel on a standard 2-inch
(50-mm) kingpin or similar 2-inch (50-mm)
diameter shaft so that it locks.

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5.2

Push on the wedge stop rod with hand
pressure. It should move in 1/4 inch (6
mm) and spring back out on release.

If the free travel is not 1/4 inch (6 mm),
adjust the distance to 1/4 inch (6 mm) by
turning the wedge stop rod, on the right
side of the top plate, clockwise to reduce
the gap and counter-clockwise to in-
crease it.

ConMet Simplex®

Disconnect the tractor from the trailer. For in-
structions, see Chapter 10 of the Business
Class® M2 Driver’s Manual

Thoroughly steam-clean the fifth wheel.

Check the fifth wheel plate for cracks. Check for
sharp edges on top; the chamfer should be 1/8
to 1/4 inch (3 to 6 mm).

When the wheel is locked, the safety latch must
swing free and fall freely into position. See

Fig. 1

The lever bar and operating handle must be in
proper alignment. See

Fig. 2

. Replace any bent

or misaligned lever bar or operating rod.

Check all clinch pins for cracking or damage.
Replace any clinch pin that shows signs of dam-
age.

Measure the top plate lift. See

Fig. 3

7.1

Level the fifth wheel plate to a horizontal
position.

7.2

Measure the height from a stationary
mounting point, such as the frame rail to
the top of the fifth wheel plate.

f310353b

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Lubricant Grooves

Safety Latch

Lock Control Handle

Mount

Fig. 1, Simplex Series Fifth Wheel

04/11/2011

f310470

Operating Handle

Lever Bar

Fig. 2, Lever Bar and Operating Handle Alignment

f310475

04/11/2011

A. Extended Top Plate Lift Height
1.

Fifth Wheel Top Plate

Fifth Wheel Frame Mount

Frame Rail

Lifting Point

Static Top Plate Height

Fig. 3, Measuring Fifth Wheel Top Plate Lift

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7.3

Pry up on the fifth wheel plate below the
pin boss, and measure the vertical move-
ment.

NOTE: The bracket connection provides a
9/32-inch (7-mm) vertical clearance to pro-
vide cushioning and to avoid downward pin-
loading while retaining minimum plate lift.

7.4

If the plate lift exceeds 5/16 inch (8 mm)
as a result of wear or rubber deteriora-
tion, install new, standard or oversized
bracket-shoe rubber pads; see the Sim-
plex Fifth Wheel Operating and Mainte-
nance Manual for replacement instruc-
tions.

NOTE: Do not measure plate lift immediately
after a trailer has been uncoupled from the fifth
wheel. The rubber may have taken a temporary
set, which will normally recover after being un-
coupled for a short period of time.

Check the clearance between the kingpin and
the jaw of the fifth wheel. If the clearance is
greater than 1/8 inch (3 mm), dial out the slack
using the eccentric jaw pin. For detailed instruc-
tions, see the Simplex Fifth Wheel Operating and
Maintenance Manual.

Check all mounting bolts for signs of fatigue, and
tighten them to the proper torque. For torque
specifications, see

Group 00

. Inspect all angles,

plates, and brackets for cracks or other damage.

10. Replace cracked, worn, or damaged parts with

new parts. Replace all loose mounting bolts with
5/8–11 SAE grade 8 bolts, grade C locknuts, and
hardened washers. Do not re-use bolts, nuts,
and washers on fifth wheel mountings.

11. After inspecting the fifth wheel, lubricate all mov-

ing parts with a chassis or multipurpose grease.
See

Maintenance Operation 31–03

for lubrica-

tion instructions.

Holland

Thoroughly steam clean all fifth wheel compo-
nents before inspection.

Check the fastener torques on the fifth wheel
assembly and fifth wheel mounting. Tighten bolts
and nuts as needed. Replace missing or dam-
aged bolts. Replace bent, worn, or damaged
parts with genuine Holland parts.

Using a Holland Kingpin Lock Tester, part num-
ber TF-TLN-1000 or TF-TLN-5000, check the
operation of the locking mechanism by opening
and closing the locks. See

Fig. 4

31–03 Fifth Wheel Lubricating

Fontaine

Tilt the top plate forward (the front of the fifth
wheel is down) and apply grease to each bearing
area through the zerk fittings located on each
side of the top plate just to the front of the
bracket pins. Continue to apply grease until it is
coming out of the back of the bearing. It may be
necessary to raise the rear of the fifth wheel with
a pry bar to open up the pocket slightly and
allow the grease to flow through. A substantial
amount of grease may be required initially to fill
the reservoir.

Tilt the fifth wheel rearward (the rear of the fifth
wheel is down) and repeat the greasing proce-
dure. Rock the top plate back and forth several
times to spread the grease over the bearing sur-
face.

Inspect the trailer kingpin plate and top surface
of the fifth wheel to make sure each is properly

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f310887

A. The nut and washer should be snug against the fifth

wheel.

B. The locks should be completely closed around the

kingpin.

Fig. 4, Holland Fifth Wheel Properly Closed

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greased. A liberal coating of grease should be
applied to the complete surfaces of both the
trailer kingpin plate and the top surface of the
fifth wheel.

NOTE: Do not use a lube plate (high density
polyethylene) on top of the fifth wheel or on the
kingpin instead of grease without prior approval
by Fontaine Fifth Wheel. The additional thick-
ness of this material can prevent the proper op-
eration of the fifth wheel and may cause a dan-
gerous condition.

Lubricate the fifth wheel prior to opening and
closing. Grease the jaw and wedge with a screw-
driver and distribute the grease along the full
length of the jaw and wedge mating surfaces.
See

Fig. 5

. Open and close the fifth wheel sev-

eral times to further distribute the grease.

Lightly oil other moving parts in the fifth wheel.

Apply grease to the top plate. Spread grease all
over the mating surface of the top plate. Be sure
the grease pockets built into the top plates are
full of grease.

ConMet Simplex

Apply a heavy coat of grease to the top plate, either
through the grease fittings located on the underside
of the top plate, or by direct application.

Apply grease directly to the lock mechanism.

If lubrication fittings are present, lubricate the inter-
face of the steel bracket shoe and bracket trunnion.

Holland

Using a water-resistant lithium-base grease,
apply grease to the top plate. Grease the mount-
ing bracket supports through the zerk fittings.
See

Fig. 6

Using a light oil or diesel oil, lubricate the cam
track and pivot. See

Fig. 7

31–04 Trailer Electrical

Connector Lubricating

In some cases, failure of trailer cables occurs due to
intrusion of chloride-based road deicing chemicals
into the trailer connector. Once inside the connector,
the chloride-based chemicals corrode the brass ter-
minals and create bridging between positive and
ground terminals.

NOTE: The use of soap is not recommended for
cleaning the electrical connector, as some
soaps may increase the corrosion process.

Wash out any existing grease, dirt, and corrosion
on the trailer connectors with electrical contact
cleaner spray.

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Pull Handle

Jaw

Wedge

Fig. 5, Fontaine Fifth Wheel

09/06/2001

f310886

A. Apply grease to the top plate.
1.

Zerk Fitting

Fig. 6, Holland Fifth Wheel

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