A bushing on a car is a lining that provides a cushion between two metal parts. Bushings are made of rubber or polyurethane and are used in a car's suspension system to decrease friction. This allows the car to absorb surface vibrations, providing a smoother ride.
Bushings become worn from exposure to heat, cold and motor oils and must be replaced. Evidence of worn bushings includes excessive road noise, loose steering and clunking noises that come from underneath the car. Bushings are also used in the gear shifts of manual transmissions and in anti-roll bars. In one of the first uses of bushings, the engine of Chrysler's 1932 model Plymouth was suspended on rubber mounts to cut down noise and vibrations.