What You Need to Know Shock Absorbers

Shock Absorbers are a part of your vehicle's suspension system. They are responsible for cushioning the up-and-down movement of your vehicle's springs, which reduces vibration and makes driving smoother.
How Shock Absorbers Work
The basic structure of shock absorbers consists of a piston in a reservoir of fluid, called oil. The piston moves up and down with the up-and-down movement of your car's suspension, which compresses and expands the fluid. The fluid creates pressure on both sides of the piston head and on the base of the cylinder. The oil expands when the piston moves up and contracts when it moves down, which dampens the springs.

How Long Does a Shock Absorber Last?
Like any other part on your car, a shock absorber's effectiveness slowly deteriorates over time. This can be due to driving conditions and road surface. If you notice that your shocks are losing their effectiveness, it's time to have them replaced.
How to Test Your Shock Absorbers
If your shocks have started leaking, it's time for them to be replaced. This happens because the oil inside them leaks out. The oil is essential for damping bumps on the road, so it will stop working if it runs out.
How to Maintain Your Shock Absorbers
Maintaining shock absorbers on light trucks and sport utility vehicles (SUVs) is different from that on cars. SUVs and trucks travel at much higher speeds over rough roads, so the bodies of their shock absorbers must be larger to help dissipate heat created by the axle and body's motions. Also, many trucks and SUVs have air-spring rear suspensions, which allow them to offset shifts in ride height to prevent bottoming out.