GMC 1976 ZEO 6083 Maintenance Manual page 544

9- 12 STEERING
STEERING GEAR AND PUMP DIAGNOSIS CHART (Cont'd .)
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 5176-1, adapter fitting
J 22326, connect gage to both hoses.
4. Open hand valve on gage .
5 . Start engine, allow system to reach operating
temperatures and check fluid level adding any fluid
if required . When engine is at normal operating
temperature, the initial pressure read on the gage
(valve open) should be in the 80-125 psi range.
Should this pressure be in excess of 200 psi-check
the hoses for restrictions and the poppet valve
for proper assembly .
6. Close gate valve fully 3 times. Record the
highest pressures attained each time . (Note: do not
leave valve fully closed for more than 5 seconds
as the pump could be damaged internally) .
(a) If the pressures recorded are within
1250-1350 psi and the range of readings are within
50 psi, the pump is functioning within specs.
(b) If the pressures recorded are high, but do
not repeat within 50 psi, the flow controlling
valve 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 the low listed spec .,
replace the flow control valve and recheck. If the
pressures are still low, replace the rotating
group.
s
Condition Possible Cause Correction
5. Tires not properly in- 5 . Inflate to recommended pressure .
flated .
NOTE : If checks 1 through Further possible causes In order to diagnose conditions
5 do not reveal cause could be : such as listed in 6, 7, 8, 9 a
of hard steering, follow test of the entire power steering
the procedure below to system is required .
determine fault.
6. Sticky flow control
valve.
7. Insufficient pump
pressure output .
8. Excessive internal
pump leakage.
9 . Excessive internal gear
leakage.