See Figure 1
Front wheel alignment is the position of the front wheels relative to each other and to the vehicle. It must be maintained to provide safe, accurate steering with minimum tire wear. Many factors are involved in wheel alignment and adjustments are provided to return those that might change due to normal wear to their original value. The factors which determine wheel alignment are dependent on one another; therefore, when one of the factors is adjusted, the others must be adjusted to compensate. Descriptions of these factors and their affects on the car are provided below.
The procedure for checking and adjusting front wheel alignment requires specialized equipment and professional skills. The following descriptions and adjustment procedures are for general reference only. Do not attempt to check and adjust the front wheel alignment without first making a thorough inspection of the front suspension components.
Camber angle is the number of degrees that the centerline of the wheel is inclined from the vertical. Camber reduces loading of the outer wheel bearing and improves the tire contact patch while cornering.
Caster angle is the number of degrees that a line drawn through the steering knuckle pivots is inclined from the vertical, toward the front or rear of the car. Caster improves directional stability and decreases susceptibility to crosswinds or road surface deviations.
STEERING AXIS INCLINATION
See Figure 2
Steering axis inclination is the number of degrees that a line drawn through the steering knuckle pivots is inclined to the vertical, when viewed from the front of the car. This, in combination with caster, is responsible for directional stability and self-centering of the steering. As the steering knuckle swings from lock to lock, the spindle generates an arc, the high point being the straight-ahead position of the wheel. Due to this arc, as the wheel turns, the front of the car is raised. The weight of the car acts against this lift and attempts to return the spindle to the high point of the arc, resulting in self-centering, when the steering wheel is released, and straight-line stability.
Toe-in is the difference of the distance between the centers of the front and rear of the front wheels. It is most commonly measured in inches, but is occasionally referred to as an angle between the wheels. Toe-in is necessary to compensate for the tendency of the wheels to deflect rearward while in motion. Due to this tendency, the wheels of a vehicle, with properly adjusted toe-in, are traveling straight forward when the vehicle itself is traveling straight forward, resulting in directional stability and minimum tire wear.
CASTER AND CAMBER ADJUSTMENTS
See Figures 3, 4, 5 and 6Shim Type
ALL MODELS EXCEPT ELDORADO, 1980 AND LATER SEVILLE, AND 1967-76 ECCENTRIC TYPE
Caster and camber are controlled by shims between the frame bracket and the upper suspension arm pivot shaft.
To adjust caster, remove shims from the front bolt and replace them at the rear bolt, or vice versa. To adjust camber, add or remove the same number of shims from each bolt.
Keep in mind when loosening the bolts that the upper suspension arm is supporting the weight of the vehicle. Loosen the bolts only a sufficient amount to remove the shims.Strut and Eccentric Type
FULL SIZE MODELS 1967-76
Caster is adjusted by lengthening or shortening the struts at the frame crossmember. To adjust, turn both nuts an equal number of turns in the same direction. Lengthening the strut increases negative caster. One turn of the nuts changes caster approximately 1 / 2 degree.
Camber is adjusted by turning the camber eccentric located in the steering knuckle upper support. Turning the eccentric changes the camber by moving the steering knuckle in or out. Loosen the ball joint stud locknut and tap the knuckle to free the eccentric, being careful not to strike the brake line or ball joint seal. Turn the eccentric until camber is within specifications. The stud must be positioned to the rear of the eccentric in order to maintain correct steering geometry. Tighten the ball joint stud nut to 60 ft. lbs. (81 Nm).
1967-85 ELDORADO AND 1980-85 SEVILLE
Caster and Camber are controlled by Cams located on the bolts which support the upper control arms.
To adjust caster, increase the cam offset in the rear and decrease the cam offset in the forward cam, or vice versa. To adjust camber the cam offset should be adjusted to the same amount for both the front and rear cam.
1986-89 ELDORADO AND SEVILLE
Caster on these models is not readily adjustable.
Camber is adjusted by means of an adjusting bolt on the lower end of the strut assembly. Loosen both strut-to-knuckle bolts, then turn the adjustment bolt until camber comes into specification.
See Figure 7
Toe-in is adjusted after the caster and camber adjustments are carried out. Adjust the toe-in by loosening the clamps on the tie rod sleeves, and turning the sleeves an equal amount in the opposite direction, to maintain steering wheel spoke alignment while adjusting toe-in.