Alignment: Service and Repair

DESCRIPTION
The angles at which suspension components operate in relation to the vehicle and wheel centerlines are calculated during vehicle design to provide maximum tire contact with the road throughout the full range of suspension travel. The checking of caster, camber and wheel toe-in or out is the measurement of these suspension angles at the wheels, and the possible adjustments are performed to ensure that the tires make maximum contact with the road at all times and cause the vehicle to track in a straight line when the front wheels are centered. Proper alignment of the front and rear wheels with the vehicle chassis and each other is essential for acceptable handling and to minimize tire wear.

Prior to checking wheel alignment, ensure that tires are properly matched (same size tires on each axle set), correctly inflated and uniformly worn. Ensure that wheel bearings are properly adjusted and that suspension components are not damaged or worn. Wheel alignment should be checked with the vehicle unloaded, as any abnormal or uneven loads affect ride height which, in turn, affects suspension operating angles (wheel alignment).

Only wheel toe-in or out is adjustable on these models. Caster and camber are not adjustable. However, they should be checked as possible causes of handling or tire wear complaints. If caster and camber are not within limits suspension components should be inspected for wear and damage, and replaced as needed. If control arms, stabilizers and bushings are in good condition, check vehicle body for distortion at suspension mounting points or for collision damage.

TOE-IN & STEERING WHEEL CENTERING ADJUSTMENT
If the steering wheel is not properly centered when vehicle is driven straight ahead, mark its position with a piece of tape across the gap between steering wheel hub and steering column shroud.

If toe-in is to be adjusted, the operation can be combined with steering wheel centering. But, to avoid complications, one should be completed before starting the other. To center the steering wheel, the tie rods must be turned into one tie rod end and out of the other, in equal amounts to avoid changing the toe setting. This shifts the steering rack right or left, turning the pinion, steering column and wheel to its desired position. Center steering as follows:
1. Mark the tie rod and tie rod ends with paint or a grease pencil to indicate their original relative positions.
2. Loosen and back off the tie rod end jam nuts, then release the steering gear boot clips. Ensure boots are free on the tie rods to avoid twisting.
3. Screw tie rods into one tie rod end and out of the other, depending on which way the steering wheel is to be moved and how much. Example: if left tie rod is screwed in and right tie rod is screwed out, the steering rack moves to the left and the steering wheel movement is counterclockwise as seen from the drivers seat. For clockwise correction, the rack must be moved to the right. If the road wheels are positioned and locked in the straight ahead position during this operation, using the steering wheel tape mark as a starting point, the wheel will turn during adjustment and the centered position can be judged visually. One revolution of the tie rods will result in a steering wheel correction of approximately 19°. Check marks on tie rods and tie rod ends, to ensure tie rods are turned equal amounts. Adjust toe-in as follows:
a. Loosen jam nuts at tie rod ends and release clips at small ends of steering gear boots, ensuring boots are free on tie rods so they will not be twisted when tie rods are turned.
b. Turn tie rods into or out of tie rod ends an equal amount on each side to keep steering wheel centered.
c. When toe-in is within specifications, torque tie rod end jam nuts to 42-50 ft lb, then ensure steering gear boot ends are positioned in the reduced-diameter sections of the tie rods and install boot clips.