Since there are many variations in power steering pump pressure test procedures and pressure specifications, use your vehicle manufacturer's specific procedures and specifications.
The following is a typical power steering pressure test.
- With the engine stopped, disconnect the pressure line from the power steering pump, and connect the gauge side of the pressure gauge to pump the outlet fitting. Connect the valve side of the gauge to the pressure line.
- Start the engine and turn the steering wheel fully in each direction two or three times to bleed air from the system. Be sure the fluid level is correct and the fluid temperature is at least 176° (80°C). A thermometer may be inserted in the pump reservoir fluid to measure the fluid temperature.
During the power steering pump pressure test with the pressure gauge valve closed, if this valve is closed for more than 10 seconds, excessive pump pressure may cause power steering hoses to rupture, resulting in personal injury.
Do not allow the fluid to become too hot during the power steering pump pressure test. Excessively high fluid temperature reduces pump pressure. Wear protective gloves and always shut the engine off before disconnecting gauge fittings, because the hot fluid may cause burns.
- With the engine idling, close the pressure gauge valve for no more than 10 seconds, and observe the pressure gauge reading. Turn the pressure gauge valve to the fully open position. If the pressure gauge reading does not equal the vehicle manufacturer's specifications, repair or replace the power steering pump.
- Check the power steering pump pressure with the engine running at 1,000 rpm and 3,000 rpm, and record the pressure difference between the two readings. If the pressure difference between the pressure readings at 1,000 and 3,000 rpm does not equal the vehicle manufacturer's specifications, repair or replace the flow control valve in the power steering pump.
- With the engine running, turn the steering wheel fully in one direction, and observe the steering pump pressure while holding the steering wheel in this position. If the pump pressure is less than the vehicle manufacturer's specifications, the steering gear housing has an internal leak and should be replaced or repaired.
- Be sure the front tire pressure is correct, and center the steering wheel with the engine idling. Connect a spring scale to the steering wheel and measure the steering effort in both directions. If the power steering pump pressure is satisfactory and the steering effort is more than the vehicle manufacturer's specifications, the power steering gear should be repaired.
A power-steering pump mounted to an engine.