G 30 Van V8-454 7.4L VIN N TBI (1995)
Power Steering Pump: Testing and Inspection
Power Steering System Test
NOTES:
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All tests are made with engine idling at normal operating temperature.
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Check idle speed adjustment and, if necessary, adjust to correct specification.
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J-25323-A power steering analyzer will measure flow rate in addition to pressure.
1. Place container under steering gear or pump.
2. With engine Off, disconnect pressure hose at steering gear or power steering pump. Thread female adapter into pressure hose and male adapter
into gear or pump. Connect J-25323-A analyzer hoses to adapters.
3. If J-25323-A has never been used it will be necessary to bleed power steering system. analyzer gate must be open during this procedure.
4. Add power steering fluid to pump if required.
5. Run engine at idle speed with gate valve open and record flow (A) and pressure (B).
a. If flow is below 2 Gallons Per Minute (GPM), pump may need repair, but continue test.
b. If pressure is above 150 psi., check hoses for restriction and check steering gear.
6. Partially close gate valve to build 620 psi. Record flow (C).
a. If flow (C) drops more than one GPM under flow (A), disassemble pump and replace ring, rotor and vanes. Replace pressure plates if worn or
cracked. Replace all O-ring seals when reassembling pump. Continue test.
7. Completely close and partially open gate valve three times. Record gate closed pressure.
NOTE: Do not allow valve to remain closed for more than five seconds.
8. Check pressure specifications. If pump pressure recorded is 100 psi. lower than minimum specification listed, replace flow control valve in pump.
If pressure recorded is above maximum specification listed, flow control valve in pump should be removed and cleaned or replaced. If system is
exceptionally dirty, both steering gear and pump must be completely disassembled and cleaned before further use.
9. Increase engine speed from idle to 1500 RPM. Record flow (E).
a. If flow (E) varies more than 1.0 GPM from flow (A), flow control valve should be removed and cleaned or replaced.
10. Turn steering wheel lightly against both stops. Record pressure and flow (F).
a. Pressures developed at both stops should be nearly the same as maximum pump output (D). At the same time, flow should drop below 0.5
GPM.
b. If pressure does not reach maximum output or flow does not drop below specified valve, excessive internal leakage is occurring. Remove and
disassemble steering gear, then remove control valve.
11. Turn steering wheel in both directions and release quickly while watching pressure gauge. Needle should move from normal pressure reading and
snap back as wheel is released. If it comes back slowly or sticks, rotary valve in steering gear is sticking. Remove, disassemble and clean rotary
valve. If system contains excessive dirt and foreign material, disassemble and clean pump and gear.
12. If problem still exists, steering and front suspension must be thoroughly examined.
