JAC HFC4DA1-2C engine. Service Manual — part 40

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PowerSteering

PowerSteering System

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Steering

Steering

Steering

Steering System

System

System

System

Applied models: SUNRAY products manufactured by JAC

Subject

Page

Instruction

Instruction

Instruction

Instruction and

and

and

and Operation

Operation

Operation

Operation

Steering System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

Explosive View of Steering System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Introduction of Steering System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Diagnosis

Diagnosis

Diagnosis

Diagnosis and

and

and

and Testing

Testing

Testing

Testing

Steering System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

Operating Principle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Inspection and confirmation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 156
Fault Symptom Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..159

Removal

Removal

Removal

Removal and

and

and

and Installation

Installation

Installation

Installation

Removal and Installation of Steering System. . . . . . . . . . . . . . . . . . . . . . . . . . 164
Removal and Installation of steering wheel. . . . . . . . . . . . . . . . . . . . . . . . . . ... 167

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Instruction

Instruction

Instruction

Instruction and

and

and

and Operation

Operation

Operation

Operation

Steering

Steering

Steering

Steering System

System

System

System

Summary of Power Steering System
With the purpose of reducing the working intensity of drivers, the power steering system is firstly installed on
heavy-duty vehicles. However, with the increase of high speed demand and load on the steering wheel, the power
steering has become necessary and its application range has been widened. The advantages of the power steering
system are as follows:

It reduces the steering force applied on the steering wheel, especially in the case of static steering and low-speed
steering with large steering angle, the assistance is obvious.
It enhances the steering sensitivity.
It reduces the impact on the steering wheel in the case of ground kick back.
In the case of certain tire burst, it may prevent the wheel from swerve thus it improves driving safety.
It enables the steering wheels to bear larger loads and increase the freedom of general arrangement.

The power steering system consists of:
Vehicle power steering system consists of the power steering gear, power steering pump, power steering oil reservoir
and hydraulic line. The power steering gear is the actuator of the steering system hydraulic booster; the steering oil
pump associates with the engine, playing a role in hydraulic power supply for the system; the steering oil reservoir
possesses the function of storing, cooling and filtering of steering oil.
The structure of the power steering system is shown as follows:

Structural Drawing of Power Steering System

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Instruction

Instruction

Instruction

Instruction and

and

and

and Operation

Operation

Operation

Operation

Structural

Structural

Structural

Structural Brief

Brief

Brief

Brief Introduction

Introduction

Introduction

Introduction of

of

of

of Rack-and-pinion

Rack-and-pinion

Rack-and-pinion

Rack-and-pinion

Power

Power

Power

Power Steering

Steering

Steering

Steering Gear:

Gear:

Gear:

Gear:

The rack-and-pinion power steering gear consists of the
control valve, mechanical steering gear and power
steering pump. The control valve is a structurally
advanced and high sensitivity rotary valve and the
mechanical steering gear is a rack-and-pinion one.
Control Valve:
As is shown in the under figure: As a normally open
rotary valve, the control valve consists of 1 torsion bar,
2 input shaft, 3 valve pocket and other parts and inputs
the hydraulic oil into two oil chambers on the left and
right

through

the

pre-open

clearance

between

abovementioned 2 input shaft and 3 valve pocket.
Structural Drawing of Control Valve

1. Torsion bar

2.Input shaft

3.Valve pocket

Mechanical Steering Part:
The mechanical steering part is a rack-and-pinion one,
consisting of three parts as the gear shaft, rack piston
assembly and steering link.
Power Steering Pump:
The power steering pump has a metal casing and the
internal rack piston of the pump divides it into two oil
chambers on the left and right which are connected to
two oil ports of the control valve.
Operating Principle

Intermediate Position:
In the case of vehicle straight running (without any
movement of the steering wheel), the hydraulic oil
supplied by the oil pump goes into the oil inlet and then
goes through the pre-open clearance of the rotary valve.
At this moment, because there is no movement of the
rotary valve, the hydraulic oil returns to the oil reservoir
and the oil pressures in the two working chambers of the
steering gear are the same that no assistance is
generated.
In the Process of Steering:
In the case of steering wheel turning, there will be
changes of the valve slot clearance between the valve
pocket and the input shaft and there will be oil pressure
differential formed by the hydraulic oil flowing into
these

two

working

chambers.

The

oil

pressure

differential acts on the piston, pushes it to overcome the
steering resistance and generate displacement in order to
drive the steering link assembly to move and realize the
power-assisted steering.
In the Process of Return:
After the completion of steering, the force on the
steering wheel disappears. With the elastic force effect
of the torsion bar, the input shaft returns to a relatively
equilibrium position with the valve pocket and the oil
pressure differential between the two working chambers
of the steering gear disappears correspondingly. Then,
with the self-aligning torque effect of the front wheel,
the vehicle will return to the position of straight running
until the position has been reached.
Road Feel Effect:
The road feel effect is the ability to produce the steering
feel. When there is a force applied on the steering wheel
by the driver, the force acts on the torsion bar of the
steering gear simultaneously to make the torsion bar
twisted and deformed. However, the deformation
depends on the steering resistance of wheels. With the
increase of the steering resistance, the deformation
increases. Therefore, the driver may determine the
changes of the steering resistance according to the force
he applies on the steering wheel in order to realize the
“road feel “effect.

Oil inlet

Connecting to the

right chamber

Oil return

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Power

Power

Power

Power Steering

Steering

Steering

Steering Oil

Oil

Oil

Oil

Inspection

Inspection

Inspection

Inspection of

of

of

of Fluid

Fluid

Fluid

Fluid Level:

Level:

Level:

Level:

1.

The fluid level inspection should be carried out in
the case of engine flameout.

2.

Confirm that the fluid level is between MIN and
MAX.

Notice:

Notice:

Notice:

Notice:

The fluid level should not exceed the maximum value
(MAX mark) to avoid power steering oil leakage.
Recommended Oil: ATF-Ⅲ
3.

Do not reuse the drained power steering oil.

Inspection for Steering Oil Leakage
Inspect the hydraulic joint for the existence of oil
leakage, cracks, damages, looseness and wears.
①

Start the engine and make the oil temperature in the
power steering oil reservoir to reach 50 ～ 80℃
（122～176°F）with the engine idling.

②

Make full lock turns of the steering wheel to the
left and right for several times.

③

Hold the steering wheel in the locking point
position for 5 seconds and inspect carefully for the
oil leakage at the same time.

④

In the case of oil leakage at the joint, loosen oil
pipe nuts and retighten them with the specified
torque.
Tightening Torque: 57～63N.m
Notice:

Notice:

Notice:

Notice:

Do not excessively tighten the joint nuts to avoid
O-ring, gasket and joint damages.

⑤

In the case of oil leakage from the power steering
pump, please inspect the power steering pump.

⑥

Inspect the steering gear dust boot for oil
agglutination.

Air Bleeding of Hydraulic System
In the case of incomplete air bleeding, there may be the
following symptoms:

�

Bubbles in the power steering oil reservoir

�

Abnormal noise in the power steering pump
Notice:

Notice:

Notice:

Notice:

In the operation of power steering pump, there may
be liquid noise which does not affect system

performance or durability.

1.

Turn off the engine and make full lock turns of the
steering wheel to the left and right for several
times.
Notice:

Notice:

Notice:

Notice:

Fill the power steering oil reservoir with oil and
turn the steering wheel to make the fluid level to or
above the MIN mark.

2.

Start the engine, hold the steering wheel in the
locking point position for 3 seconds with the
engine idling and inspect for oil leakage.

3.

Repeat Step 2) for several times with an interval of
3 seconds.
Notice:

Notice:

Notice:

Notice:

When the steering wheel is in the locking point
position, do not hold it for more than 10 seconds to
avoid power steering pump damage.

4.

Inspect the oil for bubbles and white foreign
matters.

5.

In the case of incomplete bubble or white foreign
matter elimination, please turn off the engine and
repeat Step 2) ~3) after complete elimination.

6.

Turn off the engine and inspect the fluid level.
Notice:

Notice:

Notice:

Notice:

Inspect whether the fluid level of the power
steering oil reservoir changes in the range of 5mm
in the cases of engine operation and engine
flameout.
If the fluid level is not in the abovementioned
range, repeat air bleeding for the system.

Change of Power Steering Oil:
1.

Lift front wheels of the vehicle.
Notice:

Notice:

Notice:

Notice:

The front wheels should be fixed with a rigid
support.

2.

Remove the oil return pipe from the power steering
oil reservoir and block the oil return port of the oil
reservoir.

3.

Connect the oil return pipe with a general oil pipe
and drain the power steering oil to a vessel.

4.

Start the engine, turn the steering wheel to the left
and right and drain the power steering oil.
Notice:

Notice:

Notice:

Notice:

It is necessary to refill the power steering oil and

Fracture of the hose

Fracture of the oil pipe

Hose clamp

Oil pipe nut

Eyebolt

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keep the fluid level between MIN and MAX to
avoid dry friction of the power steering pump.
Excessively

lone

engine

operation

is

not

appropriate. In the case of decreasing fluid level of
the steering oil to MIN, it is necessary to turn off
the engine.

5.

Connect the oil return pipe and refill with new
power steering oil to the standard fluid level.

6.

In the case of unsatisfactory power steering oil
quality, repeat Step 2) ~5).
Notice:

Notice:

Notice:

Notice:
After oil change, carry out system air bleeding.
Inspect Pulley Tension of the Power Steering

Pump:
Apply a force of 100N in the upward center of the
V-belt between the power steering pump and the
engine crankshaft, the deflection of the belt shall in
the range of 11.7 ～ 15.3mm.In the case of
out-of-range deflection, loosen adjusting bolts of
the tension pulley and adjust the belt tension to
make it qualified.

Steering

Steering

Steering

Steering Wheel

Wheel

Wheel

Wheel

On-car Inspection:
1.

Inspection of Installation

①

Inspect the installation of the steering gear
assembly, front suspension, axle and steering
column.

②

Inspect the steering wheel for its movement
clearance in the cases of steering wheel upward and
downward, leftward and right ward and axial
movements.

③

Inspect mounting nuts and bolts of the steering
gear assembly for their looseness.

2.

Inspection of Steering Wheel Free Play

①

Turn the steering wheel to make the front wheels in
the straight-ahead position, start the engine and
then turn the steering wheel slightly to the left or
right until front wheel movement. At this moment,
measure the displacement of the steering wheel on
its outside edge.
Free Play of the Steering Wheel: 30mm

②

When the measured value exceeds the standard
value, inspect the installation of every steering
column connector and the steering mechanism.
Carry out correction or part replacement according
to actual situations.

③

If the free play exceeds 30mm, turn off the engine,
keep front wheels in straight running and apply a
force of 5N on the steering wheel circle for the
inspection of the free play. The free play should not
exceed 10mm.If the free play exceeds 10mm,
inspect whether the steering gear is qualified.

④

If the free play is still a limit value, make the
steering wheel to the intermediate position, apply a
force of 4±0.6N on the steering wheel circle and
then inspect the free play.

Standard Value: <15mm

⑤

If the free play exceeds the standard value, remove
the steering gear and inspect the total torque of the
pinion.

3.

Inspection of Intermediate Position

①

Confirm the proper installation of the steering gear
assembly, steering column and steering wheel.

②

After wheel alignment, carry out intermediate
position inspection. Please refer to “Inspection of
Front Wheel Alignment”.

③

Park the vehicle straight-ahead and confirm that the
steering wheel is in the intermediate position.

④

Loosen lock nuts of the tie rod and carry out fine
tuning of the adjusting lever by turning it to the left
and right to confirm whether the steering wheel is
in the intermediate position.

4.

Inspection of Steering Wheel Static Steering Force

①

Park the vehicle on a horizontal and dry ground
and pull up the parking brake lever.

②

Start the engine.

③

Keep the engine operating and rise the temperature
of

the

power

steering

oil

to

its

working

temperature.
Notice:

Notice:

Notice:

Notice:

The tire pressure should in the range of its standard
value.

④

Turn the steering wheel for 360° from its
intermediate position, inspect the steering force of
the steering wheel for its obvious fluctuation.
Steering Force of the Steering Wheel: < 34N
Permitted Fluctuation: < 5.9N

⑤

If the steering force of the steering wheel exceeds
the specified value, please inspect or adjust the
following items:
a.

Damages of lower swing arm and ball joint of
the steering tie rod

b.

Gear preload of the steering gear and angular
moment of the steering tie rod ball joint.

c.

Torque of the lower swing arm ball joint

5.

Inspection of Steering Wheel Self-return
Notice:

Notice:

Notice:

Notice:

In the case of slow or quick turn, confirm whether
there are differences of the acting force and

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returnability between the left and right side.
It is necessary to carry out this step on safe ground
and under safe traffic condition and pay attention to
your safety.

①

Turn the steering wheel for 90°, drive with the
speed of 35Km/h, maintain the state for several
seconds and then release the steering wheel, the
returnability should be 70% at least.
Notice:

Notice:

Notice:

Notice:

In the case of rapid turning of the steering wheel,
there may be a transient feel of “arduous”due to
insufficient oil supply during idling and it is not a
fault.

6.

Inspection of Front Wheel Steering Angle

①

After the inspection of front wheel toe-in, inspect
the steering angle of the front wheel. Place the
front wheel on the steering angle measuring device
(front wheel alignment steering wheel) and inspect
the maximum steering angles of inner and outer
wheels on the left and right.
Inner Wheel:
Outer Wheel:

②

In the case of engine idling, make full lock turns of
the steering wheel to the left and right to measure
the steering angle.
If the measured value is not in the standard range,
adjust the tie rod.
The adjustment of the steering angle is as follows:
When the steering angle exceeds the standard value,
loosen lock nuts of the left and right steering tie
rods, rotate the left and right steering tie rods
respectively with a wrench to adjust the steering
angles to the standard values and then tighten the
lock nuts with a tightening torque of 45 ～ 55N.m.
In the length adjustments of the left and right
steering tie rods (length shown in the following
figure), pay attention to adjust them to the same
value for the left and right steering tie rods
（208.7mm,in reversed directions）

Notice:

Notice:

Notice:

Notice:

When the steering angle of the inner wheel exceeds
the standard value, adjust the tie rod at this side to
rotate outward and the steering angle of the inner
wheel will increase; When the steering angle of the
outer wheel exceeds the standard value, adjust the
tie rod at this side to rotate outward and the
steering angle of the outer wheel will decrease.
Notice:

Notice:

Notice:

Notice:

The adjustment of the toe-in is interrelated with
those of the wheel alignment parameters and the
steering angle.

7.

Inspection of Ball Joint Dust Boot

①

Press the dust boot with hand to inspect it for crack
or damage.

②

In the case of cracked or damaged dust boot, it is
necessary to replace the tie rod ball joint.
Notice:

Notice:

Notice:

Notice:

In the case of cracked or damaged dust boot, the
ball joint may be damaged jointly.

8.

Inspection for Angular Moment of Steering Tie
Rod Ball Joint

①

Swing the tie rod rapidly for 10 times.

②

Measure the swing resistance of the tie rod with a
spring scale.
Standard value: 2～5 N.m
If the measured value is not in the range of
standard value, please replace it.

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Inspection and Replacement of Steering Mechanism
Parts:
Inspection of Rack Piston Assembly:
Inspect the straightness accuracy for the intermediate
rack of the rack piston assembly and the maximum
deviation is 0.15mm. Inspect the tooth face for
exfoliation and impression, verify whether there are
cracks or damages on the operating surface of the tooth
and inspect the back of the tooth for wear and damage.
If necessary, replace the rack piston assembly. Inspect
the piston ring and o-ring in the piston for damages. In
the case of defects in them, it is necessary to carry out
replacement. In the replacement, remove the piston ring
and o-ring with a flat-blade screwdriver.

Notice:

Notice:

Notice:

Notice:

Pay attention not to damage the rack. Apply some power
steering hydraulic oil on the new o-ring and install the
o-ring.
Notice:

Notice:

Notice:

Notice:

Pay attention not to expand the piston ring excessively.
Install the new piston ring onto the piston of the rack
piston assembly, apply some power steering hydraulic
oil on the new piston ring and press it out downward
with fingers.
Inspection of Valve Assembly
Inspect the gear shaft tooth surface of the spool
assembly

for

cracks,

damages,

exfoliations

or

deformations. Inspect it for its flexible rotation, in the
case of any defects, replace the spool assembly.
Steering Column
Figure for Steering Column Assembly:

Schematic Diagram of Steering Column Assembly
1.

Horn hood with airbag

2.

Steering wheel

3.

Steering column assembly

4.

Connecting shaft with universal joint

5.

Protective cover

6.

Free

upward and downward adjustment

and

locking device of the steering wheel

Inspection of Steering Column:
①

Inspect

the

steering

column

for

cracks,

deformations or other damages, in the case of such
defects, carry out relevant replacement.

②

Inspect the spline of steering column shaft for wear
or broken tooth, in the case of such defects, carry
out relevant replacement.

Original Figure of Power-assisted Steering Gear Box

Notice:

Notice:

Notice:

Notice:

In the case of separation of the steering column and
steering gear assembly, rotation of steering wheel may
lead to clock spring damage. Therefore, it is necessary
to fix the steering wheel to prevent it from rotation.
①

Power-assisted Steering Gear Box
Inspect the oil pipe joint for looseness and
damages.
Inspect the fixed bush of the power steering gear
for wears or other damages.
Inspect the rack and pinion for their smooth
operations and wears.
Inspect the gear preload.
a.

Rotate the gear with the speed of 4~6 seconds
per turn and measure the gear preload in the
whole travel range of the rack.
Standard value: 0.6～1.3N.m

b.

If the measured value exceeds the specified
value, adjust the plug

firstly

and then

reinspect the gear preload.

c.

If the specified gear preload can not achieved
after plug adjustment, inspect or replace the
plug assembly.

②

Steering Tie Rod
Inspect the angular moment of steering tie rod.
a.

Swing the tie rod rapidly for 10 times.

b.

Measure the swing resistance of the tie rod
with a spring scale.
Standard value: 2～5 N.m
If the measured value is not in the range of
standard value, please replace it.
Notice:

Notice:

Notice:

Notice:

In the case of no excessive clearance of the tie
rod under the slow swing condition, even
though the measured value is lower than the
standard value, the tie rod can be applicable.
If the measured value is lower than 4.3N.m, it

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is necessary to replace the tie rod.

③

Tie Rod Dust Boot

Inspect the dust boot for damage, in the case of
such defect, please carry out replacement.
Inspect the dust boot for its correct mounting
position.
Post-installation Inspection
Make full lock turns of the steering wheel to the
left and right for several times to verify its flexible
operation.

Inspection

Inspection

Inspection

Inspection and

and

and

and Replacement

Replacement

Replacement

Replacement of

of

of

of Steering

Steering

Steering

Steering Mechanism

Mechanism

Mechanism

Mechanism

Parts

Parts

Parts

Parts::::

Inspection of Rack Piston Assembly:
Inspect the straightness accuracy for the intermediate
rack of the rack piston assembly and the maximum
deviation is 0.15mm. Inspect the tooth face for
exfoliation and impression, verify whether there are
cracks or damages on the operating surface of the tooth
and inspect the back of the tooth for wear and damage.
If necessary, replace the rack piston assembly. Inspect
the piston ring and o-ring in the piston for damages. In
the case of defects in them, it is necessary to carry out
replacement. In the replacement, remove the piston ring
and o-ring with a flat-blade screwdriver.
Notice:

Notice:

Notice:

Notice:

Pay attention not to damage the rack. Apply some power
steering hydraulic oil on the new o-ring and install the
o-ring.
Notice:

Notice:

Notice:

Notice:

Pay attention not to expand the piston ring excessively.
Install the new piston ring onto the piston of the rack
piston assembly, apply some power steering hydraulic
oil on the new piston ring and press it out downward
with fingers.
Inspection of Valve Assembly
Inspect the gear shaft tooth surface of the spool
assembly

for

cracks,

damages,

exfoliations

or

deformations. Inspect it for its flexible rotation, in the
case of any defects, replace the spool assembly.

On-car

On-car

On-car

On-car Inspection

Inspection

Inspection

Inspection of

of

of

of Power-assisted

Power-assisted

Power-assisted

Power-assisted Steering

Steering

Steering

Steering Pump:

Pump:

Pump:

Pump:

Inspection of Release Oil Pressure
Notice:

Notice:

Notice:

Notice:

Prior to implementation, please confirm the belt tension.
①

Remove the oil pipe from the power steering pump
and connect the pump with a pressure gauge.

②

Open the valve and carry out air bleeding for the
hydraulic line.

③

Start the engine and turn the steering wheel for
several times to raise the oil temperature to about
50℃.
Notice:

Notice:

Notice:

Notice:

In engine start, it is necessary to keep belts and
hoses for other parts clean.

④

In

engine

idling,

close

the

pressure

gauge

completely to measure the release oil pressure.
Notice:

Notice:

Notice:

Notice:

The time for closed valve should not exceed 10
seconds.

⑤

After the measurement, open the valve slowly. If
the release oil pressure is not in the range of
standard value, please replace the power steering
pump.

⑥

After the inspection, disconnect the pressure gauge
from the hydraulic line and refill with new oil and
carry out air bleeding for the line.

Figure for Power Steering Pump Assembly

1.

Temperature gauge

2.

Power steering oil reservoir

3.

Power steering pump

4.

Pressure gauge

5.

Stop valve

6.

Joint

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Common

Common

Common

Common Fault

Fault

Fault

Fault Diagnosis

Diagnosis

Diagnosis

Diagnosis Table

Table

Table

Table

Fault

Fault Symptom

Fault Cause

Troubleshooting

Oil leakage

Oil leakage from the
power steering pump

Damage in oil seal of the power steering
pump

Replace the power steering pump oil
seal

Oil leakage from the oil
pipe and oil reservoir

High-temperature

aging

and

poor

connection etc. of the oil pipe

Replace the oil reservoir and oil pipe

Damage

Damage in the power
steering pump

Damage in oil seal of the power steering
pump

Replace the power steering pump oil
seal

Damage in power steering pump casing

Replace the power steering pump

Seizure

Low system pressure

Blockage in slide valve

Remove the slide valve, grind and clean
it in order to make it slide smoothly

Insufficient power
steering pump flow

Blockage in slide valve and spring failure

Internal pressure

relief

No pressure in steering
system

Seizure in slide valve assembly of the
steering pump, serious wear in parts

Inspect the safety valve/relief valve,
change the oil and replace the steering
pump

power steering gear

Internal

pressure

relief

in

the

power

steering gear

Inspect the safety valve/relief valve,
change the oil and replace power
steering gear

Oil seal failure in the power steering gear

Replace the oil seal or power steering
gear

Excessive early activation of the steering
limiter

Adjust the limiter

Noise

Abnormal noise in the
power steering pump

Air entrainment

Carry out air bleeding for the steering
system

Damage in drive components of the power
steering pump

Replace the power steering pump

Noise in the oil
pipe/power steering oil
reservoir

The oil pipe amplifies the noise in the
steering pump and the flow noise of liquid
which is flowing in the oil pipe is not
absorbed and superimposed so that there is
excessive large noise in the system.

It can be solved by optimizing the
matching of the steering system only
and part replacement alone can not
solve it at all. And a resonance tube can
be installed in the oil pipe.

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Fault

Fault Symptom

Fault Cause

Troubleshooting

Arduous

steering wheel

operation

Arduous turns to the left

and right of the steering

wheel

Too low oil level in the power steering oil
reservoir

Refill with oil

Air entrainment

Carry out air bleeding

Seize in the steering column or steering
link

Adjust the link.

Filter element blockage in the power
steering oil reservoir

Clean and replace the power steering oil
reservoir and change the steering oil

Damage in the power steering pump

Inspect the output operating pressure of
the hydraulic pump with a pressure
gauge

and

inspect

the

pump

for

damages; in the case of insufficient
pressure or flow in the power steering
pump, further inspect the hydraulic oil
filter and pipeline for blockage.

Poor performance of the power steering
gear

Inspect the power steering gear for
damage

Inspect

the

v-belt

for

slipping

and

looseness; in the case of gear drive, inspect
the engagement of the drive gear pair

Inspect and adjust each part

Air in the system

Inspect

for

leakage/carry

out

air

bleeding

Arduous quick turn of the

steering wheel during

idling

Low internal pressure in the power-assisted
system, such as insufficient oil supply of
the power steering pump; slipping and
looseness of the drive belt. Improper
adjustment of the relief valve; Deformation
of the high pressure oil pipe due to high
pressure oil, which may lead to pressure
hysteresis and air entrainment in the
hydraulic system.

Inspect and adjust the whole steering
system

Internal wear in the power steering pump

Replace the power steering pump and
clean the whole steering system

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Troubleshooting

Troubleshooting

Troubleshooting

Troubleshooting for

for

for

for Common

Common

Common

Common Faults:

Faults:

Faults:

Faults:

Oil leakage:
1.

Verify whether there is oil leakage in oil pipe of the
steering system, joints of the power steering oil
reservoir, power steering gear and power steering
pump.

2.

At the oil inlet of the power steering pump, in the
case of oil pipe looseness, there will be oil leakage
here. Therefore, it is not allowed to impact the oil
inlet of the power steering pump (for the oil pipe is
interference fitted into the pump body, please
handle with care)

3.

In the case of oil leakage in the joint between the
oil pipe and the high pressure oil outlet of the
power steering pump, replace the o-ring and tighten
the mounting bolts on the oil pipe. The oil leakage
fault is not related with the pump quality and there
is no need to replace the oil pump.

4.

In the case of oil leakage in the power steering oil
reservoir, if there is excessive oil filling in the oil
reservoir or poor seal of the oil reservoir joint,
when excessive engine bucking occurs, there will
be oil leakage in the power steering oil reservoir
cap under the condition of driving on rough road.
Such oil leakage occurs constantly and it should be
not considered as oil leakage in the power steering
pump or power steering oil reservoir. In this case,
clean the power steering pump and power steering
oil reservoir carry out reinstallation for them and
observe carefully and confirm the oil leakage in
order to confirm the proper oil filling and require
customers for regular maintenance and daily
cleaning.

Troubleshooting for oil leakage:
1.

Verify and inspect the oil leaky parts carefully,
replace oil seals and oil pipes and tighten joint
bolts. The tightening torque for the large nuts of the
power steering pump high pressure oil outlet is 55
～ 65N.m and it is not recommended to carry out
installation of the high pressure oil pipe and the
nuts with a torque larger than 60 N.m or the screw
thread in the power steering pump aluminum
casing may be damaged.

2.

In the case of low oil level, carry out timely
refilling of the power-assisted steering oil to the
specified value. And in oil refilling, the oil level is
not allowed to exceed the mark on the power
steering oil reservoir.

3.

Clean the leaky oil on the power steering pump,
power steering oil reservoir, oil pipe and relevant
joints for accurate distinguishing of oil leakage or
excessive oil filling.

Abnormal noise:
1.

Low oil level in the power steering oil reservoir, oil
leakage or air entrainment in the system, blocked
filter element in the power steering oil reservoir
may lead to insufficient oil suction of the power

steering pump.

2.

Dirty interior of the steering system may lead to
excessive wears in the stator, rotor, oil distributor,
end cover and input shaft.

3.

Design and installation of the oil pipe, blockage,
and bucking, excessive deformation of the oil pipe
in its installation and poor matching of the system
may lead to resonance and unsmooth system oil
inlet and outlet,etc.

4.

Overload operation of the steering system may lead
to excessive wear in the stator, rotor in the power
steering pump and further lead to irregular
movement of the oil in the pump which may
generate abnormal noise (In the case of noise
existence “shorter than 6 seconds”, turn the
steering

wheel

to

its

limiting

position,

the

generated“tehee”sound is normal).

5.

In the case of frequent and excessive long-term
limit steering of the power steering pump, there
should be lots of bubbles in the steering system.
The noise in the system decreases after oil change
and abnormal noise and lots of bubbles occur after
road test. In this case, such fault is not relative with
the performance and function of the power steering
pump and power steering gear. It is recommended
to change the steering oil reservoir and oil in it and
it is preferable to use an oil reservoir with internal
steps or curved tracks.

6.

Noise in other rotating parts of the engine, such as:
bearings in the water pump, air conditioner
compressor, tensioner, pulley, etc. eg. In the case of
loose belt, there may be “squeaks”coming from the
front end bearing of the power steering pump. eg.
After a certain time of vehicle running, when the
steering wheel is turned to left or right limit
position, abnormal noise may occur in some
vehicles. In this case, inspect the belt for there may
be changes in the required torques for the steering
system in limiting positions. And belt looseness
and slipping may generate noise on the pulley of
the power steering pump.

7.

Low mounting position of the power steering pump,
driving on extreme rough road etc. may lead to lots
of silts and oil stains on the oil pump casing which
may cause damage in the input shaft housing of the
power steering pump by foreign matters and then
corrosions by water, acid and alkali. In the case of
irregular maintenance of the whole steering system,
the ball bearing of the power steering pump may
easily burnt or seizured and abnormal noise and
arduous steering wheel operation may occur under
this condition at the same time.

8.

Looseness in the mounting brackets of the power
steering gear and power steering pump, internal
wear in the power steering gear and improper
adjustment of the pinion and rack.

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9.

Improper matching of system components before
leaving factory may lead to unable vibration
absorbing of pipeline as well as faults like
abnormal noise, failure of the system. Eg. In the
case of no noise reduction device or corresponding
vibration damper in the pipeline, there will be noise
and failure in the whole system. In this case, oil
pipe with different noise reduction effect may be
applicable instead. However, in such replacement,
there is a high demand of technical requirements
and it should be carried out by professional staff
from the manufacture for better troubleshooting.

Troubleshooting for abnormal noise:
1.

Clean the whole steering system and carry out air
bleeding for the system. Adjust belt tension or
replace the belt. Inspect and repair oil pipes, power
steering oil reservoir, power steering pump and
power steering gear, change with new power
steering oil and replace the power steering oil
reservoir.

2.

Replace the steering high pressure oil pipe and a
new

one

with

vibration

damping

effect

or

possessing good matching to the system may be
applied.

3.

Inspect other rotating parts, tension the pulley, and
clean the power steering pump and power steering
gear. In special cases, it is necessary to replace the
power steering pump or power steering gear
assembly.

Arduous steering wheel operation:
1.

Dirty interior of the power steering oil reservoir,
blockage in the filter screen or low oil level in the
power steering oil reservoir.

2.

A great quantity of air in the power steering system

3.

Foreign matters in the steering system may lead to
seizure in the flow control valve of the steering
pump, serious wear of parts in the power steering
pump and internal leakage of the pump.

4.

Excessive wear in the piston cylinder of the power
steering gear, poor sealing performance of the oil
seal, bonding or damage in the control valve.

5.

Insufficient tire pressure, interference in the power
steering pump steering column , loose connection,
looseness or slipping of power steering pump belt
or loose mounting position of the pump

6.

Loose bolts in joints of oil pipes which may lead to
steering oil leakage and insufficient flow in the
system.

Troubleshooting for arduous steering wheel operation:
1.

Inspect the power steering gear, control valve of
the power steering pump, oil reservoir filter screen

and steering oil, clean the whole power steering
system (it is preferable to clean with kerosene and
it is not allowed to disassemble the pump body.
Instead, remove bolts on the control valve chamber
of the pump and take out the pump body for simple
cleaning)

2.

In the case of dirty power steering pump, it is
necessary to clean the interior and exterior of the
power steering pump and oil pipes (it is not
allowed to clean with cotton gauze or other
multi-fiber cloth but carry out cleaning with clean
brush). Pay attention to system cleanness and there
should not be any visible impurities entering the
pump and system.

3.

Refill the oil reservoir to the specified oil level,
inspect or replace the oil reservoir.

4.

Adjust the belt tension according to specifications
and tighten coupling bolts for every component.

5.

Inspect joints of oil pipes and tighten connecting
nuts here.

6.

Replace oil pipes, the power steering pump or the
power steering gear.

Emulsible foam in the steering power oil:
Fault cause:
1.

There is air in the steering system.

2.

There is liquid leakage in the steering system.

Troubleshooting for the fault:
1.

Carry out air bleeding, inspect for oil leakage and
solve such problem.

2.

Inspect the power steering oil reservoir and refill
the oil reservoir with oil.

Vehicle deviation (Carry out test runs in two directions
on the flat ground):
Fault cause:
1.

Looseness of the steering wheel ball joint or
improper front wheel alignment.

2.

Twisted deformation or excessive wear in the
steering rod.

3.

Maladjustment of preload of racks in the power
steering gear

4.

Poor returnability of the steering wheel and
steering wheel tremble.

Troubleshooting for the fault:
1.

Adjust the front wheel alignment and steering
wheel ball joint.

2.

Refill with steering oil and carry out air bleeding.

3.

Adjust the preload of racks or repair racks in the
power steering gear.

4.

Inspect and adjust every joints in the system
according to specifications.

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Removal

Removal

Removal

Removal and

and

and

and Installation

Installation

Installation

Installation

Power-assisted

Power-assisted

Power-assisted

Power-assisted Steering

Steering

Steering

Steering System

System

System

System

1.

Disconnect the negative cable of the battery.

2.

Remove the cardan universal joint on the steering
gear box.

3.

Remove track bolts for fixing the steering column
to the cross coupling.

4.

Remove the cross shaft coupling.

5.

Lift the vehicle.

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Removal

Removal

Removal

Removal and

and

and

and Installation

Installation

Installation

Installation (Continued)

(Continued)

(Continued)

(Continued)

Power-assisted

Power-assisted

Power-assisted

Power-assisted Steering

Steering

Steering

Steering System

System

System

System

6.

Take down the cotter pin and remove castle nuts on
the joint of the tie rod ball joint and steering
knuckle.

�

Do not reuse the cotter pin.

7.

Remove the tie rod ball joint from the steering
knuckle.

Note:

Note:

Note:

Note:

After the separation of the steering tie rod and

steering knuckle, wrap the ball joint with cloth to
protect the ball joint seal.

8.

Remove the tie rod ball joint.

�

Loosen lock nuts of the tie rod ball joint.

�

Remove the tie rod ball joint.

Note:

Note:

Note:

Note:

Remember the number of turns in ball joint removal.

8.

Remove the fixed plate of the steering gear box oil
pipe and remove the oil pipe.

Note:

Note:

Note:

Note:

In the steering gear box oil pipe removal, block
the joint with a plug to avoid dirt entering.

PS

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Removal

Removal

Removal

Removal and

and

and

and Installation

Installation

Installation

Installation (Continued)

(Continued)

(Continued)

(Continued)

Power-assisted

Power-assisted

Power-assisted

Power-assisted Steering

Steering

Steering

Steering System

System

System

System

9.

Disconnect the booster oil pipe from the steering

gear box.

10. Remove the steering gear box.

Installation
1.

Reinstall the steering gear box.

2.

Install the booster pump oil pipe to the steering
gear box.

3.

Install the booster pump oil pipe to the inverter
valve and tighten the fixed plate.

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Removal

Removal

Removal

Removal and

and

and

and Installation

Installation

Installation

Installation (Continued)

(Continued)

(Continued)

(Continued)

Power-assisted

Power-assisted

Power-assisted

Power-assisted Steering

Steering

Steering

Steering System

System

System

System

Note:

Note:

Note:

Note:

In the ball joint installation, make sure that the

number of turns of the installation is the same with
that of the removal.

4.

Reinstall the tie rod ball joint in place.

�

Install the ball joint in place.

�

Tighten lock nuts of the ball joint.

Caution:

Caution:

Caution:

Caution:

Keep the steering wheel in the straight-ahead

position throughout.

5.

Install ball studs on the steering knuckle and lock
castle nuts with new cotter pins.

6.

Lower the vehicle from the lifter.

7.

Install the ball head shaft on the pinion shaft,
confirm the positional accuracy of the positioning
keyway and confirm that fastening bolts are in the
pinion slot.

8.

Align the clamped plated of the universal joint to the
steering column and carry out installation.

9.

Reconnect the negative cable of the battery.

10. Carry out air bleeding for the system according to the

specification.

11. Inspect for the front wheel alignment.