Wheel Alignment Measurement
Measuring Wheel Alignment
Steering 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/pull is defined as follows: At a constant highway speed on a typical straight road, lead/pull is the amount of effort required at the steering wheel to maintain the vehicle's straight path. 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 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. Refer to Label - Vehicle Certification, Tire Place Card, Anti-Theft and Service Parts ID, and Tire Diagnosis - Irregular or Premature 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.
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.
4. Adjust alignment angles to vehicle specification, if necessary. Refer to Wheel Alignment Specifications.
Front Camber Adjustment
1. Reach around the tire, using the appropriate extension and socket.
2. Loosen both strut to knuckle nuts just enough to allow for movement.
3. If the strut has not been modified previously, perform the following steps before continuing with the wheel alignment:
1 Disconnect the strut from the knuckle.
2 File the lower hole until the outer flange slot matches the inner flange slot.
3 Connect the strut to the knuckle.
4. Adjust the camber to specification by moving the top of the wheel in or out. Refer to Wheel Alignment Specifications.
Notice: Refer to Fastener Notice in Service Precautions.
5. Install the strut to knuckle nuts.
Tighten the nuts to 120 Nm (89 ft. lbs.).
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.
Notice: Refer to Fastener Notice in Service Precautions.
4. Tighten the tie rod jam nut (5).
Tighten the tie rod jam nut (5) to 68 Nm (50 ft. lbs.).
Rear Camber Adjustment
1. Loosen the inner lower control arm cam bolt nuts.
2. Rotate the cam bolts to the required camber specification setting.
Notice: Refer to Fastener Notice in Service Precautions.
3. Maintain the camber setting while tightening the cam bolt nuts.
Tighten the inner lower control arm (front) bolt nut to 110 Nm (81 ft. lbs.).
Important: Check the toe setting AFTER changing camber or caster.
4. Check the camber setting after tightening.
5. Adjust the camber setting if necessary.
Rear Toe Adjustment
1. Loosen the inner toe link cam bolt and nuts.
2. Rotate the cam bolt to the required toe specification settings.
Notice: Refer to Fastener Notice in Service Precautions.
3. Maintain the toe setting while tightening the cam bolt nut.
Tighten the rear suspension adjustment link lock nut to 110 Nm (81 ft. lbs.).
4. Check the toe setting after tightening.
5. Adjust the toe setting if necessary.