Shock Absorber

Most cars use hydraulic telescopic dampers filled with oil, often with a gas charge to stop foaming. They sit next to or inside the coil springs at each wheel. The spring carries the weight of the car; the damper only slows the movement. Without it the car would bounce several times after every bump.

When the wheel moves, a piston inside the damper pushes oil through small valves. This resistance turns movement into heat and calms the spring.

Worn dampers make the car float, bounce and dive under braking, and they can lengthen stopping distances. Oil leaks on the body of the damper and cupped tyre wear are typical signs.