CASTER AND CAMBER
See Figures 1 and 2
Caster is the forward or rearward tilt of the upper end of the kingpin, or the upper ball joint, which results in a slight tilt of the steering axis forward or backward. Rearward tilt is referred to as a positive caster, while forward tilt is referred to as negative caster.
Camber is the inward or outward tilt from the vertical, measured in degrees, of the front wheels at the top. An outward tilt gives the wheel positive camber. Proper camber is critical to assure even tire wear.
Caster and camber are preset by the manufacturer. They require adjustment only if the suspension and/or steering linkage components are damaged; with the exception of RX-7s and rear wheel drive 626s, caster and camber changes can only be made by replacing damaged parts.
On 1979-82 626s, caster and camber may be changed by rotating the shock absorber support. If they cannot be brought within specifications, replace or repair suspension parts as necessary.
On RX-7s, caster and camber are adjusted by changing the position of the upper strut mounting block.
Front end alignment is not a procedure for the do-it-yourselfer. Since caster and camber are best checked with an alignment machine, figures in the accompanying chart are only intended for reference. Measurement and adjustment procedures are only given here for toe-in setting, which is adjustable on all vehicles.
See Figure 3
Toe-in is the difference in the distance between the front wheels, as measured at both the front and rear of the front tires.
- Raise the front of the car so that its front wheels are just clear of the ground.
- Use a scribing block to mark a line at the center of each tire tread while rotating the wheels by hand.
- Measure the distance between the marked lines at both their front and rear.
Take both measurements at equal distances from the ground.
- Toe-in is equal to the difference between the front and rear measurements (front figure is smaller).
- To adjust the toe-in, loosen the tie rod locknuts and turn both tie rods an equal amount until the proper measurement is obtained.