Shock absorbers are a critical component for eliminating unwanted and excess motion in the body and suspension. Without shock absorbers, cars and trucks would bounce down the road in an uncontrollable fashion. Without shocks, tires would lack adhesion and braking and cornering would be somewhere between dangerous and impossible. Shock absorbers play a critical role in vehicle stability and safety.
By forcing a piston through oil, shocks develop the hydraulic friction necessary to resist unwanted and excess suspension motion. Shocks work in two directions called compression (the closing motion) and rebound (the opening motion). Shock absorbers are supposed to minimize unwanted and uncomfortable body motions such as pitch and side to side rocking. They must also keep the tire in maximum contact with the road surface.
The best way to determine whether you shocks are working properly is to drive your car or truck over familiar roads with various surfaces and bumps. And while a leaking shock is an obvious candidate for replacement, many shocks wear out without losing any oil. If your vehicle is exhibiting any of the following characteristics, then you may need new shock absorbers. The more characteristics you experience the more likely it is that your shocks should be replaced.