Pump Flow and Pressure Test - Vehicles With Hydro-Boost(R)
Steering System
Component Tests
Pump Flow and Pressure Test - Vehicles With Hydro-Boost(R)
WARNING: Do not touch the flowmeter during the test procedure or for several minutes after use. The flowmeter may become hot during use and can burn unprotected skin. Failure to follow this instruction may result in serious personal injury.
NOTE: For power steering pump flow, pressure and relief pressure specifications, refer to General Specifications/Power Steering Pump.
1. NOTICE: Make sure that the connection point will not interfere with any of the engine accessory drive components or drive belts. Damage to the analyzer or accessory drive components can occur.
Install the Power Steering Adapters and the Power Steering Analyzer Kit between the pressure line and the pressure inlet port of the Hydro-Boost(R) brake booster. Make sure the power steering analyzer gate valve is fully open.
2. Place a Dial Thermometer in the power steering pump reservoir.
3. Check the power steering fluid level. If necessary, add specified power steering fluid.
4. Install a digital tachometer.
5. NOTICE: Do not hold the steering wheel against the stops for an extended amount of time. Damage to the power steering pump can occur.
Start the engine. Place the transmission in NEUTRAL. Set the parking brake. Raise the power steering fluid temperature to 74-80°C (165-175°F) by rotating the steering wheel fully to the left and right several times.
6. With the steering wheel in the straight-ahead position, set the engine at idle. Record the flow rate and pressure readings.
- If the flow rate is below the flow rate specification, check the power steering pump-to-brake booster pressure line for kinks and restrictions.
- If the pressure reading is above the pressure specification, check all other power steering hoses and the fluid cooler for restrictions.
7. Partially close the gate valve to obtain 750 psi. Set the engine speed at idle. Record the flow rate.
- If the flow is less than the specified flow rate, install a new power steering pump.
8. NOTICE: Do not allow the gate valve to remain closed for more than 5 seconds.
Completely close and partially open the gate valve 3 times. Record the pressure relief valve actuation pressure reading.
- If the pressure does not meet the relief pressure specification, then install a new power steering pump.
9. Fully open the gate valve. While reading the pressure gauge, have an assistant gradually apply the brake pedal until the relief pressure is reached and then release the brake pedal (pressure should quickly build and release). Have the assistant gradually apply the brake pedal again to verify consistency.
- If the relief pressure can not be reached (brake pedal should be hard), install a new Hydro-Boost(R) brake booster.
- If the pressure returns slowly or sticks, check the brake pedal and bracket for sticking or binding. If the brake pedal and bracket are OK, install a new Hydro-Boost(R) brake booster.
10. NOTICE: Do not hold the steering wheel against the stops for an extended amount of time. Damage to the power steering pump can occur.
Have an assistant turn the steering wheel to the left and right stops. Record flow rate and pressure readings at the stops.
- The pressure reading at both stops should be nearly the same as the pump relief pressure.
- The flow rate should drop below 1.9L/min (0.5 gal/min).
- If the pressure does not reach the pump relief pressure or the flow rate does not drop below the specified value, excessive internal leakage is occurring. Install a new steering gear as necessary.
11. Have an assistant turn the steering wheel slightly in both directions and release quickly while watching the pressure gauge.
- The pressure reading should move from the normal back pressure reading and snap back as the steering wheel is released.
- If the pressure returns slowly or sticks, the rotary valve in the steering gear is sticking or the steering column is binding. Check the steering column and linkages before repairing the steering gear.