How to Stiffen a Rear Suspensionby Eli Laurens
The rear suspension of most automobiles and trucks can be stiffened with a few aftermarket parts. The average backyard mechanic can perform all of the steps in about two hours.
Replace the rear shock absorbers with coil-over models. The added strength of the extra spring wrapped around the shock will give a firmer ride, and increase stability when towing. They are usually direct replacements, bolting into the stock shock mounts. They have a slender coil spring over the top portion, held in place with bracers top and bottom, and must be checked for clearance before installation.
Replace the rear sway bar bushings with polyurethane. This durable material will last longer than stock bushings, and if the vehicle is over a few years old then the stock bushings are probably worn out. The "poly" bushings are available in exact sizes, and different colors. The sway bar is not a load carrying suspension part, and can be unbolted with the tires on the ground. Unbolt the bar at the bushing, press in a new bushing (with an ample amount of silicone for squeak suppression), and reuse the hardware to secure.
Replace the rear leaf spring shackles with longer dimensions. Extended shackles will raise the vehicle up, and can stiffen the ride if the leaf springs are sagging. The drive shaft, notably the pinion angle, will be tightened as well. The shackle should not be over 75 percent larger than the stock shackle, or the drive shaft may become stressed.
Add hardware that the vehicle did not come with, but was an option/upgrade for the model. A Chevrolet Z28 has an upgraded suspension when compared to a Camaro of the same year. Locate these heavy-duty parts and bolt them into place, usually into the factory mount holes. A rear sway bar, or heavier springs could stiffen the ride considerably.
- Use caution when working on suspension parts, as some are under compression. Use safety equipment when working on a vehicle.
Things You'll Need
- Polyurethane rear sway bar bushing kit
- Spring-over or "coil-over" shock absorbers
- Extended leaf spring shackles
- Do not unbolt leaf springs without jacking up the vehicle.
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.