SAGINAW Power Steering Pump: Testing

1996 Buick Roadmaster BaseSECTION Testing
NOTE: Incorrect fluid level, belt tension, idle speed or damaged pump pulley can affect test results. Correct such conditions before testing power steering system.
  1. On Fleetwood, connect Power Steering Pressure Tester (J-5176-D) or Power Steering System Analyzer (J-25323-A) in pressure line from pump. On Caprice, Impala SS and Roadmaster, remove intake duct. Remove brake control valve bracket bolts and reposition to access steering gear. Connect tester in pressure line from steering gear.
  2. On all models, open valve fully. Start and run engine until fluid reaches normal operating temperature. Bleed power steering system. See HYDRAULIC SYSTEM BLEEDING  . Check fluid level. Add fluid as necessary.
  3. With engine at operating temperature, pressure reading should be less than 150 psi (10.5 kg/cm2 ). If pressure is more than 150 psi (10.5 kg/cm2 ), inspect system for restrictions. Check for proper installation of check valve in steering gear for.
    CAUTION: To prevent pump damage, DO NOT  hold valve closed for more than 5 seconds.
  4. Completely close valve for less than 5 seconds and then open it, recording highest pressure obtained when valve is closed. Repeat procedure 2 more times. Each reading should be at least 1000 psi (70.3 kg/cm2 ).
  5. If readings are within 50 psi (3.5 kg/cm2 ) of each other, pump is okay. If readings are high and not within 50 psi (3.5 kg/cm2 ) of each other, flow control valve is sticking. Remove and clean flow control valve with crocus cloth. Flush system if dirty.
  6. If pressure readings are less than 1000 psi (70.3 kg/cm2 ), replace flow control valve, then repeat test. If pressure is still low after replacing flow control valve, replace rotor and vanes. Refer to the POWER STEERING PUMP  procedures under OVERHAUL.
  7. If pump meets specification, leave valve open. Turn steering wheel from stop to stop, recording highest pressure at each stop. If pressure at both stops is not equal to pressure recorded in step 4), steering gear is leaking internally. Repair or replace steering gear.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.