Component Tests and General Diagnostics
Component TestsSteering Linkage
Note:
^ Excessive vertical motion of the studs relative to the sockets can indicate excessive wear.
1. With the parking brake applied, perform the following:
1. 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.
2. Watch for loose steering gear mounting.
2. Another method is to raise the front wheels 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.
3. Any worn, damaged, or loose steering components should be installed new or tightened.
Turning Effort Test
Note:
^ Make sure that the front wheels are correctly aligned and the tire pressure is correct before checking the effort.
1. Park the vehicle on dry concrete and set the parking brake.
2. Insert a thermometer into the power steering oil reservoir.
Caution:
^ Do not hold the steering wheel against the stops for more than three to five seconds at a time. Damage to the power steering pump can occur.
3. Idle the engine for two to three minutes. Turn the steering wheel from stop-to-stop several times to warm the fluid to 50 - 60°C (122 - 140°F).
4. With the engine running, attach the spring scale to the rim of the steering wheel.
5. Measure the pull required to turn the steering wheel one complete revolution in each direction.
Pump Flow and Pressure Test
Warning:
^ Do not touch the flow meter during the test procedure, or severe burns and serious injury can occur.
Caution:
^ Make sure that the connection point cannot interfere with any of the engine accessory drive components or drive belts.
1. 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.
1. On some vehicles, the power steering pump high pressure port is inaccessible. If so, the power steering analyzer should be installed either at the steering gear or at a point in the high pressure line between the power steering pump and the steering gear.
2. Place a dial thermometer in the power steering pump reservoir.
3. Check the power steering fluid level. If necessary, add power steering fluid.
1. Use MERCON(R) automatic transaxle fluid (ATF).
4. Install a digital tachometer.
Caution:
^ Do not hold the steering wheel against the stops for more than three to five seconds at a time. Damage to the power steering pump can occur.
5. 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.
6. Set the engine speed to idle. Record the free flow rate and pressure readings.
1. If the flow rate is not within the specified range, the power steering pump can require repair. Continue with the test procedure.
2. If the back pressure reading is above the maximum pressure specification, check power steering hoses for kinks and restrictions.
7. Partially close the gate valve to obtain 740 psi. Set the engine speed at idle. Record the flow rate.
1. 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.
8. Completely close and partially open the gate valve 3 times. Record the relief pressure.
1. If the pressure does not meet the relief pressure specification, install a new power steering pump.
9. Set engine speed to 1,500 rpm. Record the flow rate.
1. 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 three to five seconds at a time. Damage to the power steering pump can occur.
10. 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.
1. The pressure reading at both stops should be nearly the same as the maximum pump relief pressure.
2. The flow rate should drop below 1.9 liters/minute (0.5 gallons/minute).
3. 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. Repair or install a new steering gear as necessary.
11. Turn (or have an assistant turn) the steering wheel slightly in both directions and release quickly while watching the pressure gauge.
1. The pressure reading should move from the normal backpressure reading and snap back as the steering wheel is released.
2. 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 servicing the steering gear.
Tie Rod Articulation Torque
Note:
^ This check can be done with the steering gear on or off the vehicle.
1. Disconnect the tie rod end from the front wheel spindle.
2. Move the tie rod back and forth three times.
3. Hook the spring scale over the tie rod end or the threaded portion of the tie rod and measure the force required to move the front wheel spindle tie rod.
4. If the force required to move the front wheel spindle tie rod does not meet the specifications, install a new tie rod.
Steering Gear Valve
1. With the vehicle in motion, place the transaxle in NEUTRAL and turn the engine OFF.
1. If the vehicle does not pull with the engine OFF, repair or install a new steering gear.
2. If the vehicle pulls with the engine OFF, cross-switch the front wheels.
3. If the vehicle pulls to the opposite side, cross-switch the front and rear wheels on the same side.
4. If the vehicle pull direction does not change, check the front suspension components, wheel alignment and frame alignment.