GM Prizm/Nova 1985-1993 Repair Guide

Front End Alignment

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See Figures 1, 2 and 3

Alignment of the front wheels is essential if your car is to go, stop and turn as designed. Alignment can be altered by collision, overloading, poor repair or bent components.

If you are diagnosing bizarre handling and/or poor road manners, the first place to look is the tires. Although the tires may wear as a result of an alignment problem, worn or poorly inflated tires can make you chase alignment problems which don't exist.

Once you have eliminated all other causes, unload everything from the trunk except the spare tire, set the tire pressures to the correct level and take the car to a reputable alignment facility. Since the alignment settings are measured in very small increments, it is almost impossible for the home mechanic to accurately determine the settings. The explanations that follow will help you understand the three dimensions of alignment: caster, camber and toe-in.

CASTER



Caster is the tilting of the steering axis either forward or backward from the vertical, when viewed from the side of the vehicle. A backward tilt is said to be positive and a forward tilt is said to be negative. Changes in caster affect the straight line tendency of the vehicle and the return to center of the steering after a turn. If the camber is radically different between the left and right wheels (such as after hitting a major pothole or curb), the car will exhibit a nasty pull to one side.



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Fig. Fig. 1: Caster angle affects the tracking of the steering.

Caster is not adjustable on either the Nova or Prizm. The camber angle is fixed by the proper location of all the suspension components. If caster is found to be incorrect, the cause must be determined through examination of the suspension and body parts. Bent, loose or worn components must be replaced. Recent body work must also be considered as a cause; if the shock tower is not correctly located, the camber will not be correct.

CAMBER



Camber is the tilting of the wheels from the vertical (leaning in or out) when viewed from the front of the vehicle. When the wheels tilt outward at the top, the camber is said to be positive. When the wheels tilt inward at the top the camber is said to be negative. The amount of tilt is measured in degrees from the vertical. This measurement is called camber angle.



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Fig. Fig. 2: Camber is the inward or outward tilt of the wheel on the road.

Camber affects the position of the tire on the road surface during vertical suspension movement and cornering. Changes in camber affect the handling and ride qualities of the car as well as tire wear. Many tire wear patterns indicate camber related problems from misalignment, overloading or poor driving habits.

Camber is adjustable on the Nova and Prizm by turning the adjusting cam on each front strut. Anytime camber is adjusted, toe must be checked and reset if necessary.

TOE-IN



Toe is the turning in or out (parallelism) of the wheels. The actual amount of toe setting is normally only a fraction of an inch. The purpose of toe-in (or out) specification is to ensure parallel rolling of the wheels. Toe-in also serves to offset the small deflections of the steering support system which occur when the vehicle is rolling forward or under braking.



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Fig. Fig. 3: Toe in (or out) can affect tire wear and fuel economy.

Changing the toe setting will radically affect the overall feel of the steering, the behavior of the car under braking, tire wear and even fuel economy. Excessive toe (in or out) causes excessive drag or scrubbing on the tires.

Toe-in is adjustable on both Nova and Prizm, and is generally measured either in fractional inches or degrees. It is adjusted by loosening the locknut on each tie rod end and turning the rod until the correct reading is achieved. The rods left and right must remain equal in length during all adjustments.

See Figure 4



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Fig. Fig. 4: Front Wheel ALignment

 
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