Why is my steering wheel off-center when the wheels are steered straight? An off-center steering wheel can occur for a variety of reasons and is often simply the result of neglecting to center the steering wheel before adjusting toe.
The main cause of steering wheel off-center is toe misalignment or rear axle misalignment. Toe can fall out of adjustment fairly easily as a result of daily driving, so you can imagine the effects of pounding it through 4WD trails on a regular basis.
Toe is designed to preload the steering linkage to remove play in the system. You can visualize toe angle from above; toe-in, or positive toe, is displayed when the leading edges of the tires are closer together than in the rear. Toe-out, or negative toe, is when the leading edges are farther apart. Zero toe is when wheels are pointed straight ahead and are parallel to each other. A slight amount of positive toe is preferred for most vehicles.
Improper toe angle isn't the only reason a steering wheel won't center. This phenomenon can also be caused by the steering linkage not being centered when toe was adjusted in the first place. This can be corrected by recentering the steering wheel and readjusting toe to proper specs. A bent steering arm or linkage component can also cause the steering wheel to be off-center. I've also seen this occur due to loose steering arm bolts. An off-center steering wheel contributes to tire wear because as the wheels are turned off dead center they turn toe out and increase tire scrubbing.
Before determining toe angle and/or performing adjustments, it's a good idea to start the engine and turn the steering wheel side to side to relieve pressure in the system. Then, turn the wheels straight and shut off the engine. You should also roll the vehicle back and forth a few times between measurements.
Sometimes an off-center steering wheel is accompanied by a wheel pull to one direction or the other and could be the result of a damaged component somewhere in the vehicle - a bent axlehousing could be throwing off the rear toe setting (rear toe setting is often overlooked). A bent frame or overly worn suspension bushings can also be the cause. If your wheel is off-center and also pulling, it can be as simple as incorrect tire pressure from side to side. Memory steer is another effect that is usually associated with an off-center steering wheel. This is when the steering wheel returns to an off-center position and can result in steering pull or drift after completing a turn. This can be caused by binding in the steering linkage as well as power steering system issues such as leaks or improper hydraulic pressure. Steering linkage bind occurs when proper geometry is not maintained in lifted vehicles.
Many 4x4s don't have factory provisions for adjusting caster and camber and rear toe and camber, but the front toe setting is easily adjusted. Toe is controlled by the steering linkage. By loosening the adjusters on the tie rod and shortening or lengthening the tie rod by turning the ends, toe angle can be adjusted. This should not be a substitute for regular professional wheel alignment jobs and is simply a tip that can be used to put off frequent trips to the alignment shop due to regular trips to the trail.