Chevrolet 1980 Light Duty Truck Service Manual page 204

3B3-6 POWER STEERING SYSTEM
CONDITION
Hard Steering or
lack of assist (Continued)
Low oil pressure due to restriction in
hoses:
Low oil pressure due to steering gear:
(See pump pressure test)
or fine hone. If the system contains some dirt, flush it. If
it is exceptionally dirty, both the pump and the gear must
be completely disassembled,
reassembled before further usage.
POSSIBLE CAUSE
Lack of lubricant in suspension
or ball joints.
Tires not properly inflated.
Steering gear to column misalignment.
Steering gear adjusted too tight.
Excessive friction in steering linkage.
Lower coupling flange rubbing
against steering gear adjuster plug.
Sticky flow control valve.
Frame bent.
Front springs weak and sagging.
Insufficient oil pressure.
Check for kinks in hoses.
Foreign object stuck in hose.
Pressure loss in cylinder due to
worn piston ring or scored housing
bore.
Leakage at valve rings, valve body
to worm seal.
Loose fit of spool in valve body or
leaky valve body.
Damaged poppet valve.
Fig. 3B3-5--Power Steering System Diagnosis Chart D
cleaned, flushed and
Lubricate, relubricate at proper
intervals.
Inflate to recommended pressure.
Align steering column.
Test steering system for binding with
front wheels off floor. Adjust as neces­
sary.
Check tie rod pivot points for exces­
sive friction. Replace the affected
pivot.
Loosen pinch bolt and assemble
properly.
Replace or clean valve.
Check frame for proper alignment or
cracking. Repair or replace as neces­
sary.
Check standing height. Weak or sag­
ging springs should be replaced with
new ones.
If above checks do not reveal cause of
hard steering, diagnose hydraulic
system to determine problem.
Remove kink.
Remove hoses and remove restricting
object or replace hose.
Remove gear from car for disassembly
and inspection of ring and housing
bore. Replace affected parts.
Remove gear from car for disassembly
and replace seals.
Replace valve.
Replace valve.
c. If the pressures recorded are constant, but more than
100 PSI, below the low listed spec., replace the flow control
valve and recheck. If the pressures are still low, replace the
rotating group in the pump.
CORRECTION
LIG H T T R U C K S ER V IC E M ANUAL