Torsion Bar Adjustment
Torsion bars are used on the suspensions of both cars and trucks. They provide the suspension coil springs and leaf springs offer with the added benefit of ride height adjustability. They can be designed longitudinally of transversely. Weak torsion bars or worn anchors and bushings alter the vehicle’s ride height, affecting stability and causing tire wear.
A typical longitudinally designed torsion bar is a long steel bar fitted between the frame of the vehicle and one of the control arms. It may be the upper or lower control arm, usually the lower. Located at the frame end of the torsion bar is an adjuster or key. These are sometimes referred to as hex keys and are used to apply the twisting motion needed for vehicle suspension and adjustment. The left and right side are often different and not interchangeable.
There are several factors involved in adjusting the ride height of a vehicle with torsion bar suspension. The amount of torque or twisting motion applied to the torsion bar by turning the adjustment bolt. The angle of the control arm is important. If the ride height is over adjusted, the CV joints will wear prematurely. The dimensions (thickness) of the bar itself are important. Vehicle manufacturers as well as aftermarket companies provide heavy duty bars by changing the thickness from 22mm to 24mm, etc. A manufacturer may install a thicker bar for a bigger heavier engine. They also use different materials to construct the bars depending upon the application.
Take measurements before and after adjustments are performed. A good spot would be between the lower part of the fender and the top of the wheel rim. Measure the distance from the base of the bolts head to its mating surface as a reference point. Tightening this bolt turns the key that adds twist to the torsion bar. This extra torque will apply more force to the control arm, raising the vehicle to the desired height. Always check for special procedures on different vehicles.