GMC 1976 ZEO 6083 Maintenance Manual page 545

STEERING
9- 13
STEERING GEAR AND PUMP DIAGNOSIS CHART (Cont'd .)
7 . If the pump checks to specs., leave the valve
open and turn (or have turned) the steering wheel
into both corners . Record the highest pressures
and compare with the maximum pump pressure re-
corded . If this pressure cannot be built in either
(or one) side of the gear, 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.
Alternate Power Steering System Test Procedure
NOTE :
If power steering analyzer J-25325 is
available, use it and the following procedure to
determine fault.
1. Connect Analyzer J-25323 into steering system .
Remove pressure fitting from gear and connect into
female analyzer adapter. Thread male adapter of
analyzer into gear . Connect analyzer to adapters .
Tighten both connections to 40 ft . lbs. Add power
steering fluid to pump if required .
2. Start engine . Set engine idle to specification .
Run engine for approximately five minutes . Check
power steering fluid level and add if required .
3. Record flow and pressure at idle with gate
valve fully open . If flow is below 2gpm, the pump
appears to be in need of repair, but continue
diagnosis. If pressure is above 200 psi check
hoses for restrictions and check steering gear
for poppet valve functions.
4. Partially close gate valve to build 700 psi .
Observe and record flow . If flow drops more than
1 gpm, disassemble pump and replace ring, rotor,
and vanes. If pressure or thrust plates are
cracked or worn, replace.
5. Completely close and partially open gate valve
three times (do not allow valve to remain closed
more than 5 seconds. If pressures recorded are
100 psi lower than 1250-1350 psi specifications,
replace flow control valve in pump . If pressures
recorded vary more than 50 psi, the flow control
valve should be removed and cleaned. Also check
control valve bore for dirt, chips, etc. Clean as
required . If system fluid appears contaminated,
both the gear and the pump must be completely
disassembled and cleaned.
6. Increase engine speed from idle to approxi-
mately 1500 rpm. If the flow varys more than 1
gpm, the flow control valve should be removed and
cleaned as in step 5 above.