JAC HFC4DA1-2C engine. Service Manual — part 39

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-134-

Instruction

Instruction

Instruction

Instruction and

and

and

and Operation

Operation

Operation

Operation

Rear

Rear

Rear

Rear axle

axle

axle

axle

Rear axles for two-wheel drive vehicles with dependant
rear suspensions are adopted, mainly composed of final
drive, differential and axle housing, which are the final
stage transmission mechanism in vehicle power train.
The final drive, consisting of driving gear and driven
gear, functions for changing driving direction, reducing
speed and increasing torque. Driving gear is connected
with universal joint assembly of propeller shaft through
driving gear flange at one end of spline, with its middle
part supported by two conical bearings installed
reversely for bearing axial force and tangential force and
the small end face journal of driving gear installed on

cylinder roller bearing for bearing radial force only. The
driven gear is fixed on the differential left housing by
using a set of bolts.
Differential, for realizing different rotation speed of left
and right wheels, is mainly composed of left and right
housings of differential, spider, four planetary gears and
two differential gears.
One end of rear axle shaft is connected with differential
gear with spline and the flange at the other end is
connected with wheel hub assembly with brake drum by
using bolt.

Rear Axle Exploded View

2400010R002

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-135-

1.

Driving gear flange nut

2.

Driving gear flange flat
gasket

3.

Driving gear flange

4

Flange dust cover

5

Driving gear oil seal

6

Tapered roller bearing

7

Resilient spacer

8

Driving gear

9

Driving

gear

adjusting

washer

10

Tapered roller bearing

11

Final drive housing

12

I-type hexagon nut

13

Spring washer

14

Final drive housing bolt
(Single end)

15

Final drive housing
bolt (Stud)

16

Driven gear bolt

17

Differential

bearing

adjusting washer

18

Differential bearing

19

Differential

housing

(Right)

20

Differential

gear

thrust

washer

21

Differential gear

22

Planetary gear shaft

23

Planetary gear

24

Driven gear

25

Differential housing (Left)

26

Differential housing bolt

27

Heavy spring washer

28

Bearing cap

29

Heavy spring washer

30

Bearing cap bolt

31

Rear

axle

housing

assembly

32

Normally-closed

vent

plug

33

Oil filler plug

34

Oil filler plug sealing
washer

35

Hexagon

plug

with

magnetic core

36

Drain plug sealing washer

37

Oil catcher

38

Axle shaft

39

Axle shaft oil seal

40

Lock washer

41

Nut and bolt components

42

Bearing lock nut

43

Rear brake drum

44

Rear hub outer bearing

45

Rear hub

46

Rear hub inner bearing

47

Rear hub inner oil
seal

48

Brake

assembly

(Left/Right)

49

Axle shaft bolt

50

Tapered sleeve

51

Spring washer

52

I-type hexagon nut with
fine thread

53

Tire bolt (Left/Right)

54

Outer

bolt

of

tire

(Left/Right)

55

Cross

recessed

countersunk

head

screw

56

Brake bottom plate bolt

57

Spring washer

58

I-type hexagon nut with
fine thread

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-136-

Instruction

Instruction

Instruction

Instruction and

and

and

and Operation

Operation

Operation

Operation

Application

Application

Application

Application and

and

and

and maintenance

maintenance

maintenance

maintenance

1.

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.

2.

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.

3.

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.

4.

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

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-137-

Diagnosis

Diagnosis

Diagnosis

Diagnosis and

and

and

and Testing

Testing

Testing

Testing

Inspection

Inspection

Inspection

Inspection and

and

and

and maintenance

maintenance

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.

2.

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.

3.

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)

4.

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

5.

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.

2.

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

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-138-

Diagnosis

Diagnosis

Diagnosis

Diagnosis and

and

and

and Testing

Testing

Testing

Testing

Installation

Installation

Installation

Installation and

and

and

and adjustment

adjustment

adjustment

adjustment of

of

of

of rear

rear

rear

rear axle

axle

axle

axle assembly

assembly

assembly

assembly

Please

make

adjustment

based

on

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

to

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.

.

2.

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.

3.

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.

.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-139-

Adjustment of meshing marks:

Contact status of driven gear
working flank

Causes

Adjusting

method

A-Tooth

surface

contact

area

adjustment

B-Backlash adjustment

Deflected

to addendum

High driving gear, driven gear too
far

1. Driven gear away from driving gear

2. Driving gear close to driven gear to
obtain

correct

backlash

(adding

washers)

Deflected to dedendum

High driving gear, driven gear too
close

1. Driven gear close to driving gear

2. Driving gear away from driven gear
to obtain correct backlash (reducing
washers)

Deflected to small end

High driven gear, driving gear too
close

1. Driven gear away from driving gear

2. Driving gear away from driven gear
to obtain correct backlash (reducing
washers)

Deflected to big end

High driven gear, driving gear too
far

1. Driven gear close to driving gear

2. Driving gear close to driven gear to
obtain

correct

backlash

(adding

washers)

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-140-

Diagnosis

Diagnosis

Diagnosis

Diagnosis and

and

and

and Testing

Testing

Testing

Testing

Troubleshooting

Troubleshooting

Troubleshooting

Troubleshooting

Fault

Causes

Solutions/Preventive Measures

Hub bearing sluggish

Excessive preload for hub bearing

Adjust the preload.

Bearing lack of lubricant or adoption of improper
grease

Add or change grease.

Bearing contaminated by dust

Clean and add grease.

Hub bearing sluggish

Poor camshaft lubrication or adjusting arm failed to
return

Add grease or correct faulty parts.

Wheel sticking

Return spring fracture or fatigue for brake shoe or
air chamber

Replace faulty parts.

Abnormal

driving

sound

Improper differential gear clearance

Replace washer or gear.

Excessive clearance between driving and driven
gears

Replace washer or gear.

Too small driving gear bearing preload

Adjust preload.

Abrasion or damage of differential gear, planetary
gear, spider thrust washers and etc.

Correct or replace faulty parts.

Too low oil level

Add lube oil.

Lube oil leak

Wear, looseness or damage of oil seal

Replace oil seal.

Looseness of final drive fastening bolt or damage of
sealant

Tighten bolt or reapply sealant.

Looseness of bearing support fastening bolt

Tighten bolt to the specified torque.

Looseness of drain plug or damage of lining

Tighten plug or replace lining.

Axle housing deformation due to overloading

Correct or replace axle housing.

Vent plug blockage or damage

Clean or replace vent plug.

Insufficient brake force

Overheating or deterioration of brake lining

Replace brake lining.

Improper fitting of friction lining

Correct the fitting position of brake lining.

Brake drum flooded by water

Depress the pedal slightly during running to drain

water.

Grease on contact surface between brake lining or
brake drum

Clear grease or replace brake lining.

Abnormal

braking

noise

Rivet extruded due to wear of brake lining

Replace brake lining.

Hardening or deterioration of brake lining surface

Replace brake lining.

Uneven wear or insecure installation of brake drum

Correct brake drum or tighten bolt.

Untight contact between brake shoe and brake lining

Replace rivet.

Looseness of brake shoe fixed pin

Tighten the lock screw of fixed pin.

Hub bearing wear

Replace hub bearing.

Deformation of brake drum

Replace brake drum.

Improper installation of brake shoe or damage of

return spring

Tighten fixed pin lock screw or replace return
spring.

Greasy or deteriorated brake lining

Clean or replace brake lining.

Damage of brake bottom plate

Replace brake bottom plate.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-141-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation

Rear

Rear

Rear

Rear axle

axle

axle

axle

Removal of rear axle
1.

Block the wheel front and back with anchor blocks.

2.

Loosen outside wheel nut.

3.

Jack up the rear axle.

Removal of axle shaft
1.

Loosen axle shaft nut.

2.

Remove axle shaft. If it is difficult to remove,
please use copper hammer to knock on the axle
shaft flange gently until it becomes loose.

Disassembly of wheel hub
1.

Remove lock washer.

2.

Remove hub bearing lock nut.

Attention:

Remove adjusting nut by using 7757 adjusting nut

wrench for hub bearing.

3.

Remove hub assembly.

Attention:

Attention:

Attention:

Attention:

Please apply the rear hub puller.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-142-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation (Continued)

(Continued)

(Continued)

(Continued)

Rear

Rear

Rear

Rear axle

axle

axle

axle

4.

Remove axle shaft oil seal from the end of axle
shaft sleeve.

Note:

Note:

Note:

Note:

During assembly, apply lithium base grease onto
the outer ring of axle shaft oil seal and then press it
into rear hub.

5.

Disassemble together with the inner ring of inner
bearing.

Note:

Note:

Note:

Note:

During assembly, oil seal bushing shall be pressed
into axle shaft sleeve by using special pressing die
after being heated.

6.

Remove oil seal from hub assembly.

7.

Remove outer ring of inner/outer bearing.

8.

Remove brake drum.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-143-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation (Continued)

(Continued)

(Continued)

(Continued)

Rear

Rear

Rear

Rear axle

axle

axle

axle

Disassembly of axle housing and final drive

1)

Drain gear oil from final drive.

2)

Disconnect the connection between propeller
shaft and final drive.

3)

Remove final drive assembly by using jack.

4)

Remove hose, steel tube and electric wiring
harness.

5)

Remove brake assembly.

6)

Remove rear axle.

�

Jack up the axle housing.

�

Remove U-bolt and upper/lower back plates,
lower the jack and pull out the axle housing.

Disassembly of final drive assembly
1.

Before assembly, measure and record backlash of
driving/driven gear.

Attention:

Attention:

Attention:

Attention:

After adjustment, check gear meshing status.

2.

Make assembly marks on bearing cap and housing.
The removed bearing cap and final drive housing
should be placed separately at left and right side in
pair, in order to avoid confusion.

3.

Remove bearing cap and bolt.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-144-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation (Continued)

(Continued)

(Continued)

(Continued)

Rear

Rear

Rear

Rear axle

axle

axle

axle

4.

Remove differential assembly.

5.

Remove driving gear assembly by using puller and
remove adjusting washer at the same time.

Disassembly of differential assembly
1.

Remove differential right housing.

2.

Remove differential gear and bearing washer.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-145-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation (Continued)

(Continued)

(Continued)

(Continued)

Rear

Rear

Rear

Rear axle

axle

axle

axle

3.

Measure and record planetary gear backlash.

Attention:

Attention:

Attention:

Attention:

Please hold the planetary gear spider during

backlash measurement.

4.

Remove planetary gear spider assembly and
remove planetary gear and bearing washer from
spider.

5.

Take out the differential gear and its thrust washer.

6.

Remove driven gear

7.

Remove

differential

bearing

from

differential

housing.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-146-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation (Continued)

(Continued)

(Continued)

(Continued)

Rear

Rear

Rear

Rear axle

axle

axle

axle

Removal of driving gear
1.

Remove driving gear flange nut.

2.

Remove retaining ring for shaft and remove driving
gear guide bearing.

3.

Extrude the driving gear out of bearing support.

4.

Remove adjusting washer and bearing spacer.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-147-

Removal/Installation

Removal/Installation

Removal/Installation

Removal/Installation (Continued)

(Continued)

(Continued)

(Continued)

Rear

Rear

Rear

Rear axle

axle

axle

axle

5.

Remove bearing from driving gear.

6.

Remove oil seal from bearing support.

7.

Remove inner and outer rings of bearing.

Inspection during removal

�

Check driving gear flange for wear or damage.

�

Check bearing for wear or color change.

�

Check gear for crack.

�

Check driving and driven gears for wear or
crack.

�

Check differential gear, planetary gear and
planetary gear shaft for wear or crack.

�

Check differential gear spline for wear or
damage.

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-148-

Specification

Specification

Specification

Specification

1.

Structure type of rear axle

Item

Specification

Axle housing type

Integral press-welding axle housing

Axle shaft support type

Full-floating type

Reduction gear type

Single-stage hyperboloid spiral bevel gear

Planetary gear type

2/4 planetary gear

2.

Sealant and adhesive for rear axle

Item

Specified Sealant and Adhesive

Fitting surface between rear axle housing assembly and final drive
assembly

1587 Silicon rubber

Driven gear bolt

GY-340 Anaerobic adhesive

Differential housing bolt

GY-340 Anaerobic adhesive

Final drive housing bolt

Machinery sealant 605

Internal cavity of hub

Multi-purpose lithium base grease

Parts installation of final drive assembly

10# Engine oil

3.

Rear axle wear parts list

Name

Qty.

Driving gear oil seal

1

Rear hub inner oil seal

2

Rear hub inner bearing

2

Rear hub outer bearing

2

Driving gear inner bearing

1

Driving gear outer bearing

1

Axle shaft oil seal

2

Driving gear nut

1

Differential bearing

2

Left/right friction

Respectively 2 pieces for left and right

4.

Rear axle maintenance parameter list

Item

Value

Clearance between driving and driven gears

0.15～0.20

Clearance between planetary gear and differential gear

0～0.15 mm

Rotating torque of driving gear

Without oil seal; apply gear oil 18～21Kgf.cm

Rear axle gear oil

Hyperbolic gear oil: (GL-5) 85W/90; capacity: 2.5L

Oil applied onto outer lips and lips of axle shaft oil seal and driving
gear oil seal

ZL-2 GB5671-85, multi-purpose lithium base grease

Clearance between brake lining and brake drum

0.4～0.7 mm

5.

Main tightening torque list

Bolt (nut) name

R101(N.m)

Driving gear nut

245～294

Bolt - driven gear

114.6～140.1

Differential housing bolt

68.6～88.2

Final drive housing bolt

65～93

Bearing cap bolt

132.3～171.5

Rear brake bottom plate nut

50～60

Axle shaft bolt

46-80

Small hexagon bolt for lock washer

6～12

Oil filler plug

44.1～53.9

Drain plug

44.1～53.9

RAX

RAX

RAX

RAX Rear

Rear

Rear

Rear Axle

Axle

Axle

Axle

-149-

Specification

Specification

Specification

Specification

Item

Wear limit

Wear of rear axle leaf spring retainer location hole

1mm

Outer bearing journal radial runout of left/right axle shaft sleeve

0.1mm

Middle unprocessed surface of axle shaft

Radial runout

1.5mm

End face runout of joint surface between hub and axle shaft flange

0.15mm