Page 506 - Foton Workshop Manual - Auman EST-M

DI - 452 Diagnosis - Mechanical fault diagnosis

Power steering failure

Overview

Power steering system uses the power from the engine to assist the driver to perform steering. It converts the
energy from the engine into hydraulic power, then converts the hydraulic power into mechanical
power, which is applied on the steered road wheels, assisting the driver to steer the vehicle, it is so called
power steering system.
Precautions
1. Don’t use different models of oil. Otherwise, it may cause sealing failure.
2. During dismounting, prohibit knocking and bouncing with big force. Hanle the parts carefully.
3. When dismounting the pipeline, ensure cleanliness and pay attention to the smoothness of pipeline
and oil pump oil seal gasket. If they are deformed a lot, replace them timely. Otherwise, the pipeline
may leak.
4 Since the steering gear and power steering pump are both vehicle safety-related units. There are strict
requirement on the manufacture and assembly of their parts; non-professions are prohibited from
disassembling internal parts of the power steering pump.
5. Before assembling, all the oil pipes must be clean. The pipe joints and connecting parts shall not be
impacted or scratched. Do not let foreign matters get into the oil pipe. Otherwise, the performance will
be impacted.
6. After the assembly is completed, there should be no leakage for any joint.
7. After the assembly is fixed, it shall work flexibly without stuck.
Failure phenomenon list

Failure phenomenon Possible reason Failure elimination

Fill in the dynamic steering liquor,
1. Oil level low. Air gets into the oil-way
exhaust and tighten the pipe joint
2. The belt of steering oil pump
Tightening the belt
(slippery)
The steering force increases in a
3. Steering oil pump (the flow is too
moment when turning the steering wheel Replace the steering oil pump
small)
to left or right suddenly
4. The oil pressure of oil pump is too
Replace the oil pump
low.
5. The internal leakage of steering gear
Replace the steering device
is excessive.

1. Oil level (too low) Fill oil according to the requirements
2. The belt of steering oil pump (too Adjust the tension according to the
When the engine steers, in particular
loose) specification
making a spin burn, the steerig wheel
trembles and vibrates Check the pump pressure (the pressure
3. The pressure of steering oil pump is
test is needed). If the pressure relief
insufficient.
valve is damaged, replace it

DI-452