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Chery A series. Manual - part 75

10 seconds). Repeat this step for several times to discharge all the air of the system from
the oil reservoir. Add the hydraulic oil as the oil level descends.

---- Keep the engine idling, repeat turning the steering wheel from the left limit position to

the right until there is no air bubble and foam in the oil reservoir. If the oil level
descends, fill with the oil to the specified value (max).

---- The exhaust of this type of vehicle is not easy. Please completely discharge the air bubble

left in the system. Otherwise, it would make the abnormal noise in the hydraulic power
pump.

CHECK OF THE OUTPUT PRESSURE OF POWER STEERING PUMP

The main purpose of checking the output pressure of the power steering pump is to determine
whether there is malfunction in the power steering pump or the steering pinion mechanism.
Before checking, in order to measure the output oil pressure of the power steering pump
accurately, the oil level of the oil reservoir should reach the normal position and the tension
of the drive belt of the power steering pump should conform to the standard.

Measure the output oil pressure of the power steering pump with the pressure gauge which is
connected in series with a manual valve in the system. When the engine stopped, remove the
pressure pipeline from the power steering pump, connect an end of the pressure gauge with
the connector of the pump outlet, join another end of the manual valve with the inlet nozzle
of the steering control valve, so the pressure gauge and the manual valve are connected in
series in the pressure pipeline of the power steering pump and steering control valve.

Steps for measuring the output oil pressure of the power steering pump are shown below:

---- Open the manual valve completely.

---- Start the engine and keep it idling.

---- Repeat turning the steering wheel from the left limit position to the right for several times

until the steering oil temperature reaches 80

and

℃

ensure that the oil level normal.

---- Measure the static oil pressure at the rotating speed is 800r/min. The reading of the

pressure gauge is at least 300kPa if the power steering pump functions properly.

---- Close the manual valve gradually until the pointer of the pressure gauge keeps stable and

get the reading. At that time, the output standard pressure of the power steering pump
should be at least 6.2~6.9MPa; The small reading of the pressure gauge shows that
pressure of the steering pump is too low which can not effectively complete the steering.
That means there are malfunctions in the steering power pump and therefore it should be
repaired or replaced.

CHECK OF THE TENSION OF THE BELT

If there is wear, crack or flake on the belt, please replace it in time. For checking the tension,
moderate pressure should be applied in the middle of the pulley by thumb and the
displacement of the belt should be about 10mm. If the belt is too slack, please go to the
nearby service station of Chery to adjust and repair it.

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DIAGNOSIS AND TROUBLESHOOTING OF POWER STEERING

SYSTEM

The frequent malfunctions of the hydraulic power steering system are the oil leakage,
infiltration of air, failure of the power steering pump, and damage of the steering control
valve and mechanical transmission mechanism of the hydraulic transmission mechanism. All
these malfunctions show in different forms, such as steering heavily, noise, unsmoothness,
vibration and so on. When the power steering system is in trouble, please diagnose the failure
and eliminate it at once.

Steering heavily

※Malfunction symptom

In general, the steering should be easy for a vehicle with power steering system. If it fails, the
steering would be heavy and the steering wheel would be hard to turn.

※Malfunction reason

Generally, it is caused by the invalidation or the insufficient power of the hydraulic power
steering system; Damage or improper adjustment of the mechanical transmission mechanism.
The specific reasons are shown below:

The oil reservoir leakage or oil level is lower than the specified value.

The oil tube connectors is not well sealed, leakage always happens.

The air enters the steering hydraulic loop.

The oil tube is deformed; Oil pipeline is blocked; oil pressure or flux of the oil pump is
insufficient.

The tension of the power steering pump driving-belt is insufficient and the belt slides.

The wear and leakage in the steering pump are serious, which makes the output pressure of
the oil pump lower than the standard.

·The pressure regulator oil pump fails, and the output pressure is too low.

There is internal leakage in the steering control valve and power hydraulic cylinder

The steering pinion mechanism is damaged or adjusted improperly, steering link system
components are bended, and friction force on every ball pin is too large.

The tire pressure is too low.

Front wheel alignment is not accurate.

The vehicle is overloaded seriously.

※Diagnosis and Troubleshooting

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Measure if the tire pressure is normal. If necessary, inflate it according to the specified
pressure.

Check if there is leakage in the oil tube connectors of the steering hydraulic steering system.

If there is leakage, screw them tightly. Inspect if there is damage, deformation or crack on
the oil tube. If one of the above-mentioned failures is detected, the oil tube should be
replaced.

Check the rotation movement of the steering rack & pinion mechanism at the wheel return
position and the other position, if the rotating torque is too large, check the bending of the
rack and the adjustment of the rack jacking block. If necessary, adjust the pressure of the
rack jacking block or replace the steering rack & pinion mechanism.

Check if the steering control valve is blocked or returned improperly. Replace it, if

necessary.

Remove and inspect the hydraulic cylinder and replace the damaged components.

Adjust the ball pins which locate in the connection of the steering transmission mechanism
to ensure them run smoothly.

Vibration of the steering wheel as turning

※Malfunction symptom

As the engine works, turn the steering wheel. It vibrates, especially at the limit position.

※Malfunction reason

The steering oil pump driving-belt slides.

The oil level is too low in the oil reservoir.

The air enters the steering hydraulic loop

The output pressure of the steering oil pump is insufficient.

The piston of the pressure regulator in the steering oil pump is blocked.

※Diagnosis and Troubleshooting

Check if the steering oil pump driving-belt is sliding or damaged. If necessary, tighten the
tension of the belt or replace it.

Check if the oil level of the oil reservoir reaches the specified value. If necessary, fill with
steering oil.

Check all the connectors of the steering hydraulic system to see if there is leakage of the
steering oil, and discharge the air penetrated into the oil tube.

Check the output pressure of the steering oil pump. Disassemble the pump when the

pressure is insufficient to determine if there is wear or serious internal leakage of the oil
pump; the badly leakage or clog of the pressure－limited valve and pressure regulator

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piston; Weakening of the pressure regulator spring, damage on the seal components. Find
out the malfunctions and eliminate them. If necessary, replace the oil pump.

Steering wheel floating or deflecting when the Vehicle runs straight

※Malfunction symptom

It is difficult to keep the vehicle running straight.

※Malfunction reason

The steering control valve torque rod is damaged or too gentle to overcome the transmission

resistance of the steering gear, which does not enable the valve bush return in time.

The movement of the valve bush and valve core is clogged due to the unclean oil.

The steering core of the steering control valve is deviated from the center position.

The relief piston of the steering pump pressure regulator is clamped which makes the flux of

the pump and the pressure difference between the left and right power cylinders too large.

Clearance of the steering transmission mechanism connectors are too large, the connectors
are loose or overworn.

※Diagnosis and Troubleshooting

First, check if the connectors of the steering transmission mechanism are loose, the

clearances of the components are too large, the transmission is slack, in order to eliminate
the trouble in the steering transmission mechanism.

Check if the oil is polluted. If the vehicle is new or repaired or the maintenance and
oil-change regulars are not carried out, the oil may be polluted. The polluted oil should be
replaced.

Check the steering control valve. Turn the steering wheel without starting the engine to
judge that whether the control valve can open and close smoothly. If there is abnormal,
disassemble and check it.

Finally, check if the pressure regulator of the steering pump works normally and the relief
piston is clogged. If necessary, measure the output pressure of the steering pump and then
judge it.

Steering noise

※Malfunction symptoms

There is abnormal noise when the vehicle turns.

※Malfunction reason

The noise in the steering system when the vehicle turns is normal; the noise in the early

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Content .. 73 74 75 76 ..