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1977 PONTIAC SERVICE MANUAL
replace the seal(s), after inspecting and thoroughly cleaning
the sealing surfaces. Replace the shaft only if very severe
pitting is found. If the corrosion in the lip seal contact zone
is slight, clean the surface of the shaft with crocus cloth.
Replace the shaft only if the leakage cannot be stopped by
smoothing with crocus cloth first.
Housing Or Cover Seepage
Both the power steering gear and pump assemblies are
leakage checked. However, occasionally oil seepage may
occur from the gear or pump other than the seal areas. If this
type of leakage is found, replace the leaking part.
Individual Leakage Breakdown
Fig. 3-8 shows areas to be checked for leakage. If leakage
occurs, repair or replace as necessary.
POWER STEERING SYSTEM TEST
PROCEDURE
1. Disconnect pressure hose at union of pump, use a
small container to catch any fluid which might leak.
2. Connect a spare pressure hose to pump union.
3. Using pressure gage J 5176-01 and adapter fitting J
2236, connect gage to both hoses (Fig. 3-9).
NOTE: The power steering system may be tested using
either J 5176-01 as described here or with available tool
J 25323 Power Steering Analyzer which will measure
flow rate in addition to pressure.
4.
Open valve on gage.
5. Start engine, allow system to reach operating
temperature and check fluid level adding fluid if required.
When engine is at normal operating temperature, the pressure
reading on the gage (valve open) should be in the 80- 125 psi
range. If this pressure is above 200 psi, check the hoses for
restrictions and poppet valve for proper assembly.
6. Close valve fully 3 times. Record the highest pressure
attained each time.
NOTE: Do not leave valve fully closed for more than
5 seconds as the pump could be damaged.
a. If the pressure recorded is within 50 psi, the pump is
functioning within specifications.
b. If the pressures recorded are high, but do not repeat
within 50 psi, the flow control valve in the pump is sticking.
Remove the valve, clean it and remove any burrs using crocus
cloth 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,cleaned and reassembled before
further usage.
c. If the pressures recorded are constant, but more than
100 psi below 1350 psi, replace the flow control valve and
recheck. If the pressures are still low, r'eplace the rotor and
vanes.
7. If the pump checks to specification, leave the valve
open and turn (or have turned) the steering wheel to both
stops. Record the highest pressures and compare with the
maximum pump pressure recorded. If pressure is not same
(at both stops) as maximum pressure, the gear is leaking
internally and must be disassembled and repaired.
8. Shut off engine, remove testing gage, spare hose,
reconnect pressure hose, check fluid level or make needed
repairs.
SHOCK ABSORBER DIAGNOSIS
This procedure includes both on-car and bench checks
to be performed in diagnosing shock absorber performance.
ON-CAR CHECKS
Weak
1. Check and adjust tire pressures as specified.
2. Note load conditions under which car is normally
operated.
3. If practical, ride with owner to understand complaint
before proceeding to next step.
4. Test each front and rear shock in turn by quickly
pushing down and then lifting up on the corner of the bumper
nearest the shock being checked. Use the same amount of
effort on each test and note the resistance provided by the
shock on compression and rebound. Compare with a similar
car having acceptable ride quality.
Both front shocks should provide the same feeling of
resistance as should both rears. If there is any noticeable
variation between right and left, proceed to the next step.
5. The front wheels must be supporting the weight of the
car to obtain adequate shock stroke. Also, the rear axle
should be supported at least enough to unload shock mounts.
6. Disconnect the lowest shock mountings. Stroke
shocks at various rates of speed through maximum travel in
both directions. Compare side to side for rebound and
compression resistance. Rebound resistance is normally
stronger than compression (approximately 2 to 1). It is
mandatory that right and left shocks feel comparable.
Differences between front and rear are normal. If in doubt
about condition, compare with a known good shock.
Noisy
1. Check all mounting torques (bolt and/or nut). A loose
mounting will very definitely cause a noise noticeable to the
driver.
2. If all mountings are intact, jounce the car as in Step
4 (weak) to isolate the suspected unit.
3. If practical, ride car with owner to understand
complaint before proceeding to next step.
4. Observe instructions on supporting front and rear
wheels in Step 5 (weak). Disconnect the lower mounting of
suspected shock. Completely extend to full rebound, then
exert an extra pull.
5. Other objectionable noises may be detected by
stroking. A hissing noise (orifice swish) is considered normal.
A grunt or squeal after one full stroke in both directions is
abnormal. A clicking noise on fast reverse is abnormal.
Abnormal conditions require replacement of the shock.
Leaks
1. Front shocks must be inspected through the coil
springs preferably with the wheels unsupported.
2. Rear shocks should be inspected fully extended (axle
unsupported) to expose the seal cover area.
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