Wheel alignment refers to the angular relationship between the wheels, the suspension attaching points and the ground.
On the W-Body vehicles covered by this manual, GM specifies that Four Wheel Alignment be used, since the rear suspension is independent and adjustable, not a solid beam axle used on some other Front Wheel Drive vehicles. A complete four wheel alignment check is recommended whenever a service check is deemed necessary (uneven tire wear, the vehicle pulls to one side or a major suspension component has been replaced). This check includes the measurement of all four tires. The fuel economy and tire life increases when the vehicle is geometrically aligned. Additionally, the steering and the vehicle performance is maximized.
Because four wheel alignment is critical to the vehicle's performance and safety, it should be performed by a qualified technician with the proper equipment. The latest alignment equipment uses lasers for accurate sighting and a computer for precise calculations. Below is a description of the various angles used in wheel alignment on these vehicles.