Component Tests and General Diagnostics

Fig. 4 Power Steering Pressure Gauge Connections. Except Cutlass Supreme, Fig. 4 Grand Prix, Lumina, Regal, Geo Models & 1991 Beretta, Cavalier, Corsica, Cutlass Calais, Grand Am, Skylark & Sunbird:

When performing system test procedures, power steering pressures can easily exceed 1000 psi. Extreme caution must be exercised when performing these tests to prevent personal injury.

1. Disconnect pressure hose from pump.
2. Connect a spare pressure hose to pump, then connect pressure gauge J-5176-D or equivalent between both hoses, Fig. 4.
3. Open valve on gauge, then start engine and allow it to reach operating temperature. Check fluid level and add if necessary.
4. Pressure reading should be 80-125 psi. If pressure is more than 150 psi on Corvette, 6000, 1990-91 Century, Cutlass Ciera and Cutlass Cruiser and 200 psi on all other models, check hoses for restrictions and poppet valve on steering gear for proper assembly.
5. Close valve fully three times for not more than five seconds each time. Pressure readings should show at least 1000 psi on Camaro, Caprice, Custom Cruiser, Cutlass Ciera, Cutlass Cruiser, Roadmaster, 6000 and models without T/C style pump and 1250 psi on all other models each time valve is closed.
6. If pressures recorded are high enough and within 50 psi of each other, the pump is operating normally.
7. If pressures recorded are high enough but are not within 50 psi of each other, the control valve in the pump is sticking. Remove but do not disassemble control valve and clean it with crocus cloth or a fine hone to remove any burrs. Flush system if fluid appears to be dirty.
8. If pressures recorded are less than specification in step 5, replace control valve and recheck. If pressures are still low, inspect pump rotor and vanes.
9. If pump pressure meets specifications, leave valve open and turn steering wheel to both stops. Record highest pressures and compare with maximum pump pressure recorded. If pressure is not the same (at both stops) as maximum pressure, steering gear is leaking internally and must be disassembled and repaired.
10. Turn off engine and remove pressure gauge and spare hose, then reconnect pressure hose and restore fluid level to full level.