Measuring Wheel Alignment
MEASURING WHEEL ALIGNMENTSteering and vibration complaints are not always the result of improper alignment. One possible cause is wheel and tire imbalance. Another possibility is tire lead due to worn or improperly manufactured tires. Lead is the vehicle deviation from a straight path on a level road without pressure on the steering wheel. Refer to Radial Tire Lead/Pull Correction in Tires and Wheels in order to determine if the vehicle has a tire lead problem.
Before performing any adjustment affecting wheel alignment, perform the following inspections and adjustments in order to ensure correct alignment readings:
- Inspect the tires for the proper inflation and irregular tire wear.
- Inspect the runout of the wheels and the tires.
- Inspect the wheel bearings for backlash and excessive play.
- Inspect the ball joints and tie rod ends for looseness or wear.
- Inspect the control arms and stabilizer shaft for looseness or wear.
- Inspect the steering gear for looseness at the frame.
- Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises.
- Inspect the vehicle trim height.
- Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components.
- Inspect the fuel level. The fuel tank should be full or the vehicle should have a compensating load added.
Give consideration to excess loads, such as tool boxes, sample cases, etc. If normally carried in the vehicle, these items should remain in the vehicle during alignment adjustments. Give consideration also to the condition of the equipment being used for the alignment. Follow the equipment manufacturer's instructions.
Satisfactory vehicle operation may occur over a wide range of alignment settings. However, if the setting exceeds the service allowable specifications, correct the alignment to the service preferred specifications. Refer to Wheel Alignment Specifications.
Perform the following steps in order to measure the front and rear alignment angles:
1. Install the alignment equipment according to the manufacturer's instructions.
2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment.
3. Measure the alignment angles and record the readings.
4. Adjust alignment angles to vehicle specification, if necessary. Refer to Wheel Alignment Specifications.
IMPORTANT: When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front alignment angles.
FRONT CASTER ADJUSTMENT
The front caster is not adjustable. If the front caster angle is not within specifications, inspect for suspension support misalignment or front suspension damage. Replace any damaged suspension components as necessary.
FRONT CAMBER ADJUSTMENT
1. Loosen both strut to knuckle nuts just enough to allow for movement.
2. If the strut has not been modified previously, perform the following steps before continuing with the wheel alignment:
2.1. Disconnect the strut from the knuckle.
2.2. File the lower hole until the outer flange slot matches the inner flange slot.
2.3. Connect the strut to the knuckle.
3. Adjust the camber to specification by moving the top of the wheel in or out. Refer to Wheel Alignment Specifications.
NOTE: Refer to Fastener Notice in Service Precautions.
Fastener Notice
4. Tighten the strut to knuckle nuts to 180 Nm (133 lb ft).
FRONT TOE ADJUSTMENT
1. Ensure that the steering wheel is set in a straight ahead position.
2. Loosen the tie rod jam nut (5).
3. Adjust the toe to specification by turning the adjuster (6). Refer to Wheel Alignment Specifications.
4. Install the tie rod jam nut (5).
NOTE: Refer to Fastener Notice in Service Precautions.
Fastener Notice
Tighten
Tighten the tie rod jam nut (5) to 68 Nm (50 lb ft).