Some vehicles, particularly for the front suspension, have struts. While the terms shocks and struts often are used together, struts are a suspension assembly that includes a shock absorber, but the strut assembly also includes other suspension parts for that wheel, such as a coil spring.
Several common signs can warn you that shock absorbers or struts need replacing, such as when your vehicle bottoms out over railroad tracks, speed bumps or dips in the road, or it keeps bouncing well after the fact. Other signs of car shocks and struts in bad condition are unusual noises over bumps, excessive body lean or sway in turns, or that the front end of the vehicle dives sharply in hard braking. Bad shocks also can affect steering control and cause uneven tire wear.
Because car shocks wear out gradually, you might not notice because you get used to a looser, bouncier ride quality, much like you get used to longer stopping distances as brake pads on your car wear out.
One way to test the condition of the shocks and struts of your car is to push down hard on each corner of a vehicle. If the vehicle continues to bounce after you let go, your shocks need replacing. However, this bounce test for the shocks may require quite a bit of strength, and with many high-riding SUVs and pickup trucks, it isn’t easy to get the leverage you need for a bounce test.
Instead, you should have a qualified automotive mechanic check your shock absorbers and struts when your vehicle is on a lift, such as when you have tires rotated. The mechanic will be able to see if there are major leaks (shock absorbers are filled with fluid), worn mounts or bushings, or physical damage to the shock absorbers, such as dents, which can impair the bounce control function of the shocks’ piston or cause leaking.
Despite advice to get new shocks or new struts at specific intervals (often from those who sell replacements), such as every 50,000 miles, when you need to change them can vary by vehicle and how and where you take your ride. If your driving frequently is over bumpy, rough roads that put more stress on the shock absorbers and front struts, then you will probably need to new shocks and struts for your vehicle more often than if you drive mainly on smooth pavement. Carrying heavy loads also will wear out shocks faster.