How to Raise a Car's Suspensionby Eli Laurens
A car or truck suspension can be raised through a series of adjustments or replacement parts, giving the vehicle more ground clearance. Having a higher ground clearance can help with off-roading, easier repair or interior access. The average backyard mechanic can raise a vehicle's suspension in about three hours.
Measure the height of the vehicle on a flat surface, and decide how much to raise the suspension. Raising the suspension only an inch or two can be done with adjustments or simple bolt-on parts; extreme raising (over three or four inches) will require many new parts or lift kits.
Adjust the torsion bars to a higher rate with a hex-head wrench. Most 1970s sedans and many trucks have torsion bars in the suspension instead of springs. These bars can be adjusted from underneath the vehicle, where they are mounted to the frame rail, by turning the adjustment bolt in a clockwise direction. If the bolt is too tight to turn, jack up the wheel for that torsion bar to relieve its compression. Be sure to equalize the bars and level the vehicle.
Increase the height or rate of the coil springs. Taller coils will raise how the vehicle body sits on its frame components. The front coils can be changed out by using a spring compressor tool to hold it in place while the control arms are separated. Rear springs are normally decompressed when the rear end is raised up, and can be taken out and replaced by hand without a tool.
Install shackles onto the leaf springs, if applicable. Shackles are the H-shaped brackets that hold the leaf spring to the end of the vehicle's frame, and replacing these with longer types will raise the vehicle considerably. Some models will have front and rear leaf springs which can be raised in this way, such as older Jeeps. The shackle is removed by jacking up the vehicle, raising the center of the leaf spring to decompress it, then unbolting and replacing the shackle. Using this method can lead to problems with the drive-line angle, notably the pinion angle, and where the transmission bends to meet the rear differential with a shaft and U-bolts. Raising over two inches can lead to issues with these angles.
Install taller tires to increase the height from the ground to the differential. Many 4WD trucks will install lift kits just so that taller tires will fit underneath the body, sometimes to excess. The height of the tires is constrained by the height of the wheel well, as the front wheels must turn and large tires could rub or grind against the body. Applying one of the other steps can make taller, larger tires possible.
- Purchasing a "lift kit" will make finding the necessary parts easier.
- Raising a car's suspension will raise its center of gravity, so use caution when making sharp turns.
Eli Laurens is a ninth-grade physics teacher as well as a computer programmer and writer. He studied electrical engineering and architecture at Southern Polytechnic University in Marietta, Ga., and now lives in Colorado.