Camber is the tilting of the wheels from the vertical 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, the camber is said to be negative (-). The amount of tilt, measured in degrees, from the vertical is known as camber angle. Camber influences both directional control and tire wear. Excessive camber results in tire wear and causes the vehicle to pull or lead to the side with the most positive camber. On GM W-Body vehicles, camber adjustment is available at both the front and rear wheels.
Caster is the tilting of the uppermost point of the steering axis, either forward or backward from vertical, when viewed from the side of the vehicle. A backward tilt at the top is called positive caster (+) and a forward tilt is called negative caster (-). Caster influences the directional control of the steering, but caster does not affect tire wear. One wheel with more positive caster than the other wheel causes that wheel to pull toward the center of the vehicle. The vehicle will move or lead toward that side with the least amount of caster.
Preliminary Alignment Inspection
A knowledgeable and competent professional alignment shop will make a number of checks before attempting a vehicle alignment. Loose or worn suspension parts prevents an accurate setting of alignment angles. Checks should include:
The alignment should be checked with a full tank of fuel. The alignment shop should then check the alignment in the following order: