Component Tests and General Diagnostics
Power Steering Fluid Leak TestNote:
^ This test should only be carried out if a leak in the system has not been detected during a thorough visual inspection. Refer to Inspection and Verification. Initial Inspection and Diagnostic Overview
1. Check the power steering fluid level. If necessary, add the specified power steering fluid.
2. Remove the power steering pump reservoir cap and tightly install the evacuation cap to the power steering pump reservoir.
3. Install the hose from the fill adapter manifold tee to the evacuation cap on the power steering pump reservoir.
4. Install the vacuum pump to the evacuation cap.
5. Using the vacuum pump, apply 68-85 kPa (20-25 in-Hg) of vacuum to the power steering system.
6. Observe the vacuum gauge for 30 seconds. If the vacuum gauge reading drops more than 3 kPa (0.88 in-Hg) a leak is present.
7. Remove the vacuum pump.
Caution:
^ Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
8. Start the engine. With the engine at idle, raise the power steering fluid temperature to 74-80°C (165-176°F) by rotating the steering wheel fully to the left and right several times.
9. Visually inspect the system for leaks. If a leak is evident, repair as necessary. If a leak is not evident, add the specified UV fluorescent tracer dye to the power steering fluid. Use 14.78 mL (1/2 oz) of dye solution for every 1.89L (2 qt) of power steering fluid.
Caution:
^ Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
10. Start the engine. With the engine at idle, raise the power steering fluid temperature to 74-80°C (165-176°F) by rotating the steering wheel fully to the left and right several times.
11. Using the special tool (UV lamp), inspect the system for traces of UV dye. Repair as necessary.
Steering Gear Valve Test
12. With the vehicle in motion, place the transmission in NEUTRAL and turn the engine OFF.
^ If the vehicle does not pull with the engine OFF, repair or install a new steering gear.
13. If the vehicle pulls with the engine OFF, switch the right side front wheel to the left side of the vehicle and the left side front wheel to the right side of the vehicle.
14. If the vehicle pulls to the opposite side, switch the front wheels with the rear wheels keeping them on the same side of the vehicle.
15. If the vehicle pull direction does not change, check the front suspension components, wheel alignment and frame alignment. See WHEEL ALIGNMENT PREINSPECTION. Wheel Alignment Pre-Inspection
Steering Gear Grunt/Shudder Test
16. Start and run the vehicle to operating temperature.
17. Set engine idle speed to 1,200 rpm.
Caution:
^ Do not hold the steering wheel against the stops for more than 3 to 5 seconds at a time. Damage to the power steering pump can occur.
18. Rotate the steering wheel to the RH stop, then turn the steering wheel 90 degrees back from that position. Slowly turn the steering wheel back and forth approximately 1/12 of a full turn.
19. Turn the steering wheel another 90 degrees. Slowly turn the steering wheel back and forth approximately 1/12 of a full turn.
20. Repeat the test with the power steering fluid at different temperatures.
21. If a light grunt is heard or a low (50-200 Hz) shudder is present, this is a normal steering system condition.
22. If a loud grunt is heard, or a strong shudder is felt, purge the power steering system. If a loud grunt or strong shudder still exists, check the power steering lines/hoses for restrictions or damage and repair as necessary. If the lines/hoses are OK, install a new steering gear.
Pump Flow and Pressure Test
Warning:
^ Do not touch the flowmeter during the test procedure, or severe burns and serious injury can occur. Failure to follow these instructions may result in personal injury.
Caution:
^ Make sure that the connection point will not interfere with any of the engine accessory drive components or drive belts.
23. Install the power steering analyzer at the high pressure port of the power steering pump. Make sure the power steering analyzer gate valve is fully open.
24. Place a dial thermometer in the power steering pump reservoir.
25. Check the power steering fluid level. If necessary, add specified power steering fluid.
26. Install a digital tachometer.
Caution:
^ Do not hold the steering wheel against the stops for more than 3 to 5 seconds at a time. Damage to the power steering pump can occur.
27. Start the engine. Place the transaxle 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.
28. With the steering wheel in the straight-ahead position, set the engine speed to 2,100 rpm. Record the flow rate and pressure readings.
^ If the flow rate is below the flow rate specification, continue with the test procedure.
^ If the pressure reading is above the maximum pressure specification, check the power steering hoses for kinks and restrictions.
29. 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.
Caution:
^ Do not allow the gate valve to remain closed for more than 5 seconds.
30. 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.
31. Set engine speed to 2,100 rpm. Record the flow rate.
^ If the flow rate varies more than 3.785 liters/minute (1 gallon/minute) from the initial flow rate reading, install a new power steering pump.
Caution:
^ Do not hold the steering wheel against the stops for more than 3 to 5 seconds at a time. Damage to the power steering pump can occur.
32. Set the engine speed at idle. Turn (or 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 maximum pump relief pressure.
^ The flow rate should drop below 1.9 liters/minute (0.5 gallons/minute).
^ If the pressure does not reach the maximum 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.
33. Turn (or 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.
Steering Linkage
Note:
^ Excessive vertical motion of the studs relative to the sockets may indicate excessive wear.
34. With the vehicle on the ground and the parking brake applied, start the vehicle and carry out the following:
^ Have an assistant rotate the steering wheel back and forth 360 degrees and watch for relative motion of the studs in the steering linkage ball sockets.
^ Watch for loose steering gear mounting.
35. An additional check is with the key on, engine off (KOEO) and the front wheels raised off the ground, grasp the wheel at the front and rear and watch for excessive play or binding in the joints while trying to steer the wheels.
36. Install new components if necessary. Tighten any worn, damaged, or loose components.