CARS.COM — Bushings are cushions made of rubber, polyurethane or other materials. They're mounted on suspension and steering joints to absorb road shock, control the amount of movement in the joints and reduce noise. When bushings wear, they allow more movement. The driver may feel a shimmy from the front of the vehicle, or hear clunking or rattling noises on rough roads, when turning or in hard braking. Drivers may also experience poor handling or loose steering.

Bushings are used in control arms, stabilizer bars, ball joints, tie rods, shock absorber mounts, and other suspension and steering parts, as well as in engine and transmission mounts. They wear and crack from age, heat, exposure to road salt and lubricants, and the stress of frequent movement and weight loads.

Like the cartilage that protects knees and elbows, when bushings wear it puts more stress on the joints and connected parts. Like bone-on-bone contact, worn bushings can allow metal-on-metal contact. Worn control-arm bushings can also cause premature tire wear.

What feels or sounds like worn shocks or ball joints, or another suspension problem, may not be the fault of the part itself but the bushing that cushions joints and mounting points. A thorough inspection should reveal which is the culprit. For example, a loose stabilizer bar will allow more body lean (and perhaps noise as well) in turns, but if the bar isn't bent or broken, maybe only the bushings need to be replaced.

On the other hand, repair shops may recommend replacing the part and not just the bushings, because if the bushings are worn the part itself may not last much longer. In addition, many bushings are pressed into a metal sleeve and difficult to remove, which increases labor time and costs. On some vehicles, control arm bushings cannot be replaced separately, so the control arm itself has to be replaced.

Because of the amount of labor associated with installing new bushings on some vehicles, the overall cost can be high relative to the bushings themselves. New bushings, though, can markedly improve the ride and handling of a vehicle that's been in use for several years.