TROUBLESHOOTING CHART
(Steering Circuit)
POSSIBLE CAUSES SUGGESTED CORRECTIVE ACTION
TROUBLE: Slow steering, hard steering or loss of power assist
Overloaded Steering Axle
Malfunctioning relief valve preventing adequate sys-
tem pressure build-up
Worn or malfunctioning pump
Restricted high pressure filter or suction strainer
Reduce Axle Loading
Check system pressure. Adjust or replace relief valve.
Replace pump.
Replace filter element or clean strainer.
TROUBLE: Drift - truck veers slowly in one direction.
Rod end of cylinder slowly extends without turning the
steering wheel
Worn or damaged steering linkage
A small rate of extension may be normal on a closed
center system.
Inspect and replace linkage if necessary. Check align-
ment or toe-in of the front wheels.
TROUBLE: Wander - truck will not stay in straight line
Air in system due to low oil level, pump cavitation,
leaking fitting, pinched hoses, etc.
Loose cylinder piston
Broken centering springs (spool valve, steering valve)
Worn mechanical linkage
Bent linkage or cylinder rod
Severe wear in steering control unit
Correct oil supply problem or bleed air.
Repair or replace steering cylinder.
Repair or replace steering control unit.
Repair or replace.
Repair or replace defective components.
Repair or replace steering control unit.
TROUBLE: Slip - a slow movement of steering wheel fails to steer front wheels
Leakage of steering cylinder piston seals
Worn steering control unit meter
Repair or replace steering cylinder
Replace steering control unit.
TROUBLE: Spongy or soft steering
Low oil level
Air in hydraulic system. Probably air trapped in cylin-
ders or lines.
Service hydraulic tank and check for leakage.
Bleed air from system.
L06021 Steering Circuit Component Repair L6-23
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