WEICHAI WD10 Service Manual - page 158
Service Manual for WD10 Diesel Engine
148
(2) Hard steering
Fault phenomenon: The steering wheel is hard to turn, or cannot be turned when engine is running
but can be turned when engine is shut down, or hard to turn at engine idle speed but easy to turn
when engine is speed up.
Possible causes:
1) Check whether steering oil level is too low, which will result in insufficient oil supply of
steering pump.
2) Check whether there is too much air in steering system, or too much bubble in oil.
3) Check steering linkage or steering column for interference.
4) Check whether oil in oil cup is dirty and blocked the filter screen, result in steering pump hard
to absorb oil; Check whether steering pump or steering gear is damaged due to dirty oil.
5) Check steering system oil temperature with a thermometer, oil temperature should not exceed
100
o
C when engine running at highest speed stably, and should exceed 80
o
C for vehicle stable
traveling.
6) Steering gear limiter is improperly adjusted.
7) Damaged steering gear pressure control valve results in unable to adjust or control system
pressure.
8) Poor cleanliness of steering system——Results in wear or damage of system parts, leads to
pump internal leakage and output flow rate reduction——Pay attention to control and maintain
system cleanliness.
9) High system oil temperature——Under the circumstance of poor system cleanliness and worn
parts, the oil viscosity tends to be much smaller, directly leads to pump internal leakage and
output flow rate reduction——Try to lower the oil temperature.
10) Heavy loading——Results in system fails to continuously supply enough flow and pressure at
steering extreme position, leads to pump ablation——Try not to overload the system.
11) System oil shortage——Results in high system oil pressure or ablation of system
parts——Solve the oil leakage problem in time.
Troubleshooting:
1) Check and solve the leakage problem, fill oil and deflate the steering system;
2) Overhaul or replace the jammed steering transmission parts, such as linkage, steering column,
etc.
3) Replace the blocked filter element and dirty oil, overhaul and clean the oil cup, steering pump
and steering gear.