Hummer H1 Service Manual page 510

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POWER STEERING SYSTEM DIAGNOSIS CHARTS
The diagnosis charts are guidelines to potential system faults.
The charts list potential faults in order of probability (most
probable to least probable).
Problem
Poor Return of Steering
Steering Wheel Surges or Jerks
When Turning With Engine Run-
ning Especially During Parking
Hard Steering Effort in Both
Directions
Foaming Milky
Looking Power Steering Fluid,
Low Level and Possible Low
Pressure
05745159
Table 1 Power Steering Diagnosis Chart - part 1
Possible Cause
1. Tires under-inflated.
2. Lower coupling flange rubbing against
the steering gear adjuster plug.
3. Steering wheel rubbing against direc-
tional signal housing.
4. Binding steering linkage, or ball joints.
5. Steering gear to column misalignment.
6. Tie rod not centralized.
7. Lack of lubricant in the suspension ball
joints and steering linkage.
8. Stuck or plugged valve spool.
9. Improper front wheel alignment.
10. Steering gear adjusted too tightly.
11. Kink in return hose.
1. Low oil level in pump.
2. Loose pump drive belt.
3. Sticky flow control valve.
4. Insufficient pump pressure.
1. Low tire pressure.
2. Lack of lubricant in suspension or ball
joints (Worn/contaminated joints).
3. Binding of steering linkage, or ball
joints.
4. Steering gear to column misalignment.
5. Pump belt slipping.
6. Low fluid level in reservoir.
7. High internal leakage (steering gear or
pump).
8. Sticky flow control valve.
9. Steering gear adjusted too tight.
10. Improper front wheel alignment
1. Air in the fluid and loss of fluid due to
internal pump leakage causing overflow.
2. Hose or air leakage in reservoir line.
Steering System
While the charts outline common faults, they may not cover all
possible problem causes. Inspection and diagnosis with ana-
lyzer set J–25323 should be used to confirm a pump or gear
problem.
1. Inflate to specified pressure.
2. Loosen the pinch bolt and assemble
properly.
3. Adjust the steering jacket.
4. Replace the affected parts.
5. Align the column.
6. Adjust tie rod ends as required.
7. Lubricate.
8. Remove, clean, or replace the valve.
9. Check and adjust to specifications.
10. Adjust over-center and thrust bear-
ing preload to specifications.
11. Replace the hose.
1. Add power steering fluid as required.
2. Adjust bolt.
3. Replace or clean the control valve.
4. Test system with analyzer.
1. Adjust the tire pressure.
2. Lubricate and relubricate at proper
intervals or replace joints.
3. Replace all affected parts.
4. Align the steering column.
5. Adjust belt.
6. Fill to proper level. Inspect lines and
joints for external leakage.
7. Test system with analyzer.
8. Replace pump.
9. Adjust over-center and thrust bear-
ing reload to specifications.
10. Check and adjust to specifications.
1. Check for leak and correct. Bleed
system. Extremely cold temperatures
will cause system aeration should the
oil level be low. If oil level is correct
and pump still foams, remove pump
from vehicle and separate reservoir
from housing.
2. Check welsh plug and housing for
cracks. If plug is loose or housing is
cracked, replace housing.
8-19
Correction