Alignment: Service and Repair

PRELIMINARY CHECK
1. Ensure tires are inflated to correct pressure, and check for uneven wear.
2. Check front wheel bearings and related suspension components for damage and replace as necessary, to eliminate improper alignment due to faulty components.
3. Check steering gear and adjust as necessary.
4. Check shocks for damage and replace as necessary.
5. Rock vehicle backward and forward and bounce it upward and downward to settle vehicle prior to alignment.
6. Ensure vehicle is unloaded and on a suitable alignment rack following manufacturers' instructions. When measuring equipment is attached directly to outer end of driveshaft and front wheels are on turntables, apply brake to prevent improper vehicle movement.

Fig. 1 Measuring wheel alignment angles:

TOE SETTING
As viewed from above, the wheels must be set so that distances A and B, Fig. 1, measured at wheel rims and at axle height, are different at a given value. If distance A is smaller than distance B, the setting is known as toe-in. If Distance A is greater than distance B, the setting is known as toe-out. The toe setting is given in inches and refers to the difference between A and B. If distances A and B are the same, the toe setting is 0.
Toe setting is controlled by tie rod position. Adjustment is made by loosening the nuts at the steering knuckle end of the tie rods, and rotating the rod ends until proper toe setting is obtained.

Fig. 2 Measuring camber:

CAMBER SETTING

DESCRIPTION
Camber refers to the angle at which a wheel leans in or out as shown, Fig. 2. Positive camber is when the wheel leans outward and negative camber is when the wheel leans inward.
For setting angles, refer to specifications chart at beginning of this chapter.

Fig. 3 Measuring caster:

CASTER SETTING

DESCRIPTION
Caster angle refers to the angle at which the wheel center deviates from vertical when viewed from the side, Fig. 3.