Shock absorbers consist of two metal tubes, attached by a thin piston. The piston rides inside one of the tubes and cushions the blow from the road surface on the car by transferring that force to a hydraulic-fluid reservoir inside the tube. That fluid is contained in the tube by seals, which can fail over time. Many shock-absorber manufacturers recommend replacing shocks between 45,000 and 60,000 miles, or at the first signs of failure.
Push down and release the corner of the vehicle. If shock replacement is necessary, the corner will bounce more than twice.
Repeat step one at each of the remaining three corners of the vehicle.
Climb under the first corner with a flashlight. Inspect the shock absorber for any signs of fluid leakage. This will appear as a thin, wet line down the side of the shock. If the fluid has dried out, often it will leave behind a thin line of residue and/or dirt where the fluid leaked. If there’s a fluid loss, replace the shocks.
Repeat step three at each of the remaining corners of the vehicle.
