The do-it-yourself mechanic should not attempt to perform any wheel alignment procedures. Expensive, highly-specialized alignment tools are needed and making these adjustments blindly would most likely result in damage. The 4-wheel alignment should be performed by a certified alignment technician using the proper alignment tools.
Caster is the tilting of the upper most point of the steering axis either forward or backward from the vertical (when viewed from the side of the vehicle). A backward tilt is positive and a forward tilt is negative. Caster influences directional control of the steering, but does not affect tire wear.
Caster is affected by vehicle height; therefore, it is important to keep the body at its designed height. Overloading the vehicle or a weak or sagging spring will affect the caster. When the rear of the vehicle is lower than its normal designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster.
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 positive. When the wheels tilt inward, the camber is negative. The amount of tilt measured in degrees from the vertical is the camber angle. Camber influences both directional control and tire wear.
Camber and caster cannot be adjusted on these vehicles. If the camber is found to be out of specification, the cause should be located and corrected. Suspension parts may be damaged, bent, worn or loose. These parts should be replaced.
Toe is a measurement of how much the front of the wheels are turned in or out from the geometric centerline/thrust line. When the wheels are turned in (toe-in), toe is positive. When the wheels are turned out (toe-out), the toe is negative. The actual amount of toe is normally only a fraction of a degree. The purpose of toe is to ensure that the wheels roll parallel. Toe can be adjusted on these vehicles.
See Figure 1