Chevrolet and GMC 4x4 trucks made after 1988 use torsion bar suspension, rather than typical coil or leaf spring suspension. A torsion bar is a long rod with hex-head fittings at both ends. The rod slides through a hole in the back of the lower control arm and through a hole in the cross-member, about halfway back on the frame. The hole in the lower control arm has a matching hex shape into which the end of the torsion bar fits. The other end of the torsion bar slides all the way through the hole in the cross-member and seats in an adjusting arm at the back of the cross-member. An adjusting bolt attaches to the rear of the cross-member and pushes up on the end of the torsion bar adjuster.
Park the Chevy on a paved, level surface. Set the parking brake.
Use a tape measure to measure the distance from the top of the tire to the bottom of the fender well. Write this measurement down so you can compare measurements after you crank up the torsion bars.
Raise the front of the Chevy with a jack until the front wheels are just off the ground. Support the Chevy with jack stands.
Follow the torsion bar from the rear of the lower control arm to the frame cross-member. Look at the back of the cross-member and you will see the adjusting arm and bolt. Use a ratchet and socket to tighten the bolt. Count exactly the number of turns you turn the bolt. Turn the adjusting bolt on the other side the same number of turns.
Raise the front of the Chevy. Remove the jack stands and lower the Chevy to the ground. Measure the tire to fender well distance again so you can see how far you raised the Chevy.
