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Engine JAC HFC4DA1-2C. Manual - part 153

RAX

RAX Rear

Rear

Rear Axle

Axle

-135-

Driving gear flange nut

Driving gear flange flat
gasket

Driving gear flange

Flange dust cover

Driving gear oil seal

Tapered roller bearing

Resilient spacer

Driving gear

Driving

gear

adjusting

washer

Tapered roller bearing

Final drive housing

I-type hexagon nut

Spring washer

Final drive housing bolt
(Single end)

Final drive housing
bolt (Stud)

Driven gear bolt

Differential

bearing

adjusting washer

Differential bearing

Differential

housing

(Right)

Differential

gear

thrust

washer

Differential gear

Planetary gear shaft

Planetary gear

Driven gear

Differential housing (Left)

Differential housing bolt

Heavy spring washer

Bearing cap

Heavy spring washer

Bearing cap bolt

Rear

axle

housing

assembly

Normally-closed

vent

plug

Oil filler plug

Oil filler plug sealing
washer

Hexagon

plug

with

magnetic core

Drain plug sealing washer

Oil catcher

Axle shaft

Axle shaft oil seal

Lock washer

Nut and bolt components

Bearing lock nut

Rear brake drum

Rear hub outer bearing

Rear hub

Rear hub inner bearing

Rear hub inner oil
seal

Brake

assembly

(Left/Right)

Axle shaft bolt

Tapered sleeve

Spring washer

I-type hexagon nut with
fine thread

Tire bolt (Left/Right)

Outer

bolt

tire

(Left/Right)

Cross

recessed

countersunk

head

screw

Brake bottom plate bolt

Spring washer

I-type hexagon nut with
fine thread

RAX

RAX Rear

Rear

Rear Axle

Axle

-136-

Instruction

Instruction and

and

and Operation

Operation

Application

Application and

and

and maintenance

maintenance

Hyperbolic gear is of strict lubrication requirement
and only the specified hyperbolic gear oil can be
added instead of using ordinary gear oil or being
mixed with ordinary gear oil; otherwise, early wear
of tooth surface shall be caused, resulting in
excessive wear of gear.

As for bevel gear of rear axle final drive that is
selected and adjusted before delivery, removal and
adjustment

are

unnecessary

under

ordinary

condition but are necessary in case of gear wear,
backlash over the specified data or excessive end
play of bearing, or parts damaged in need of
replacement.

Clear earth and dust on the rear axle housing vent
plug frequently. Remove and clean it during
Stage-I maintenance in order to ensure air passage
unobstructed, because the air passage obstruction
shall lead to pressure increase inside the rear axle
housing, giving rise to oil leak at driving gear oil
seal and joint position. Please check the lube oil
level inside housing also.

�

Please change lube oil during the first Stage-II
maintenance of new vehicle. Change the lube oil
for rear axle housing after running for 40000Km or
24 months. Drain the gear oil out of rear axle
housing, add kerosene for cleaning, add new lube
oil of Grade (GL-5) 85W/90 after the kerosene is

drained completely. No ordinary gear oil can be
adopted.

Change

lube

oil

after running for

80000Km or 48 months and since then change oil
every 50000Km of running. Check oil quality
every four times of Stage-II maintenance; in case
of any color change, lean, or other kinds of
deterioration, please change with new oil.

�

Check the wear condition of brake lining and brake
drum. After new vehicle running for 40000Km or
using 24 months, check the wear condition of brake
lining and brake drum, measure the thickness of
brake lining worn badly (standard value: 4.6mm,
limit value: 1.0mm) . When the thickness of brake
lining is below the limit value, please replace the
brake lining.

During Stage-III maintenance, you should remove
rear axle, clean internal cavity and final drive
assembly, and tighten every bolt and nut to the
specified torque.

Precautions:

�

Weight loaded on vehicle should be no more than
the maximum allowable load.

�

During running, please don’t release the clutch
abruptly to improve barrier overtaking ability of
vehicle; otherwise, the gears may be damaged due
to impact.

RAX

RAX Rear

Rear

Rear Axle

Axle

-137-

Diagnosis

Diagnosis and

and

and Testing

Testing

Inspection

Inspection and

and

and maintenance

maintenance

Inspection and maintenance for rear axle
1.

Check parts by using special measuring apparatus
or tools.
Determine if the part can be used or not on the
basis of maintenance standard. Repair or replace
damaged parts as required. If one part damaged in a
pair of parts makes the clearance over the specified
limit, please replace this part or replace it together
with its matched part accordingly.

In order to prevent failure, please replace those
parts still within but nearly approaching to the
repair or wear limit before the limit is exceeded.

Check carefully the appearance of each part by
visual inspection or red pigment osmosis method.
In case of any abnormality listed below existed on
the outer surface, please repair or replace relevant
parts accordingly.

�

Uneven wear

�

Eccentric wear

�

Scratch

�

Crack

�

Malformation

�

Failure or weakening (of spring)

�

Bending deformation

�

Abnormal noise (of bearing)

�

Looseness

�

Color change or sticking

�

Deterioration (of brake lining)

All rubber parts, such as O-rings, oil seals, washers
and etc. should be discarded after removal instead
of being applied again.

In case of abnormal noise or vibration in drive
system, please measure the total clearance of rear
axle and then determine whether to remove final
drive assembly or not.

Park the vehicle on flat ground with transmission and
transfer case placed at neutral position; have the vehicle
jacked up after the parking brake lever is applied. Turn

the flange clockwise to the end and mark in pair
properly on the flange dust cover and final drive
housing; turn the flange counterclockwise to the end to
measure

the

distance

between

two

marks

(limit

clearance: 6mm) ; if the clearance is beyond limit, it is
indicated excessive gear clearance of rear axle, so please
make proper adjustment after removal.
Abnormal noise is a kind of noise, mainly referring to
impact sound or shrieking occurs under different
conditions (such as speed, road condition), some of
which shall disappear gradually after running-in while
some shall increase constantly. The latter situation is
mainly caused by improper assembly or adjustment. If
the parts are normal, the abnormal noise can generally
be eliminated by adjusting the assembly clearance of
parts.
6.

Brake failed to return means the brake is locked
and cannot be applied again after braking, which
can be solved by adjusting the brake assembly
adjusting clearance.

Installation and adjustment of rear axle assembly
1.

Install the wheel hub assembly with brake drum in
the reverse order of removal, during which the
adjustment listed below should be performed:
Adjustment of rear hub bearing clearance:
Tighten the bearing nut until the brake drum cannot
or hardly move, loosen the bearing nut a little by
1/6 ～ 1/8 circle and rotate the brake drum; the
tangential force measured at tire bolt without
contact between brake lining and brake drum
should be 2.98 ～ 4.97 N.m or the brake drum can
be rotated by hand freely.

Adjustment of rear brake clearance:
This brake is servo brake whose brake clearance is
adjusted automatically instead of manually.
Please observe the above mentioned procedures

and requirements to perform actual maintenance.

RAX

RAX Rear

Rear

Rear Axle

Axle

-138-

Diagnosis

Diagnosis and

and

and Testing

Testing

Installation

Installation and

and

and adjustment

adjustment

adjustment of

of rear

rear

rear axle

axle

axle assembly

assembly

Please

make

adjustment

based

the

flowing

requirements after the final drive assembly is installed:
1.

Preloading of driving gear inner/outer bearing:

�

During the assembly of final drive, the tapered
roller bearing should be of certain preload,
which

means

eliminate

the

bearing

clearance and also apply certain preload,
aiming to reduce the axial displacement
caused by axial force generated in the course
of bevel gearing and improve the bearing
rigidity of axle and thus to ensure normal
meshing of bevel gear pair. However, please
avoid excessive preloading, for it shall result
in low drive efficiency and acceleration of
bearing wear.

�

Adjustment of driving gear bearing preload:
Install the driving gear oil seal with the
tightening torque of driving gear flange nut
and

ensure

proper driving

gear

bearing

preload when the driving gear is not meshed
with driven gear. Add or reduce adjusting
washers of driving gear bearing between inner
and outer bearings of driving gear to realize
the preload adjustment. The preloading torque
shall increase with the reduction of adjusting
washers but decease with the adding of
adjusting washers.

Adjustment of differential bearing preload:

�

Adjustment of differential bearing: Adjust the
differential bearing to gain proper preload,
with 0.05～0.08mm interference on both sides.
Without the meshing between driving and
driven gears, apply gear oil onto rotary part of

bearing. The friction torque at starting should
be 1.764 ～ 2.058N.m. No axial runout of
driven gear occurs after the adjustment.

�

Adjustment of differential gear clearance:
Measure the differential gear backlash at the
planetary gear with dial indicator.
Attention: Measure at more than three points.
Standard value: 0 ～ 0.15mm; limit value:
0.3mm.

Adjustment of driving/driven gear backlash and
meshing trail

�

Adjustment of driving/driven gear backlash:
Please refer to table for normal meshing
clearance and backlash of driving and driven
gears. During the adjustment of backlash,
perform measurement at four positions evenly
distributed along the periphery of driven gear.
The measuring head of dial indicator should
be vertical to the surface of measured points.

�

Adjustment of driving/driven gear meshing
trail:
Apply red lead powder onto the driving gear
teeth and then rotate the driving and driven
gears repeatedly, so there is red trail on both
working surfaces of driven gear. If the trail on
positive/reverse rotation working surface is
located at the medium tooth height nearer to
the small end as shown in the table below, the
meshing trail position should be adjusted
through adjustment of driving gear adjusting
washer and differential bearing adjusting
washer.

Content .. 151 152 153 154 ..