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Engine JAC HFC4DA1-2C. Manual - part 159

PS PowerSteering

PowerSteering

PowerSteering System

System

- 160 -

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

PS PowerSteering

PowerSteering

PowerSteering System

System

- 161 -

Troubleshooting

Troubleshooting for

for

for Common

Common

Common 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.

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)

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.

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.

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.

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.

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

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.

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

its

limiting

position,

the

generated“tehee”sound is normal).

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.

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.

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.

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.

PS PowerSteering

PowerSteering

PowerSteering System

System

- 162 -

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.

Replace the steering high pressure oil pipe and a
new

one

with

vibration

damping

effect

possessing good matching to the system may be
applied.

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.

A great quantity of air in the power steering system

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.

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.

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

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)

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.

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

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

Inspect joints of oil pipes and tighten connecting
nuts here.

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.

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.

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.

Twisted deformation or excessive wear in the
steering rod.

Maladjustment of preload of racks in the power
steering gear

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.

Refill with steering oil and carry out air bleeding.

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

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

PS PowerSteering

PowerSteering

PowerSteering System

System

- 163 -

Removal

Removal and

and

and Installation

Installation

Power-assisted

Power-assisted Steering

Steering

Steering System

System

Disconnect the negative cable of the battery.

Remove the cardan universal joint on the steering
gear box.

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

Remove the cross shaft coupling.

Lift the vehicle.

Content .. 157 158 159 160 ..