An alignment job involves setting up the proper camber, caster, toe, and sometimes other steering and suspension angles.
Before an alignment is done, it is important to make sure all chassis parts are in good shape. If a bushing or suspension joint is worn, it will move more than the design of the parts allow for and that can cause the wheels to tilt at a different angle under certain conditions.
An example: If an outer tie rod end has some slack in the socket, it will allow the steering motion of the wheel to be off by however much of an angle the slack allows. On top of this, as the wheels are straightened on the alignment rack, whichver direction they were just pushed will be the direction that takes up the slack. Aligning to this position may show correct alignment on the alignment rack, but when driving forces are applied, the toe in/out is suddenly off by a considerable degree.
- Outer Tie Rod Ends
- Inner Tie Rod Ends
- All Control Arm Bushings
- Ball Joints
- Wheel Bearings
- Strut Mount
- Steering Knuckle
- Rack & Pinion
- Pitman Arm
Ideally, while you're working on a vehicle, you check everything, but this is the list of things
Related: How to Check Wheels For Play
Toe In For Thrust Force
Many front-wheel drive vehicles have some toe-in built into the default alignment because then the engine drives the wheels, the forces naturally apply some toe-out as they work against the suspension and bushings.
Thrust Force & Aftermarket Polyurethane Bushings
Since thrust force needs to be considered because of the flex in bushings, if stiffer bushings (such as ones made out of polyurethane instead of rubber) are installed to reduce the flex, the amount of thrust force compensation will need to be reduced.
DIY Driveway Alignment by Ratchets & Wrenches
In this video, Iman Pourshirazi shows you how to do a DIY alignment on a flat surface, perhaps like your driveway.