Your vehicle's tires are the only points of contact between the machine and the road. Struts and Shocks make sure that your tires remain on the ground, but if they aren't in great condition they will make you airborne. Fortunately, it's never too late to fix them.
Your car's suspension allows you to safely traverse uneven terrain and bumps. The springs cope with acceleration, deceleration, turns and bumps, but the weight of the car controls oscillation. Still, the weight of the car alone cannot fully control oscillation, which can lead to wheel bounce. Wheel bounce is both difficult to control, and could even cause your vehicle to lose traction.
The easiest way to test shocks is through their daily performance, but can also be determined via a "bounce test". In a deserted parking lot, start with the car idling. Accelerate hard and quickly brake hard. If the rear end bounces up, your rear struts or shocks are the culprit and need replacing. If the nose dips down when you brake, your front struts or shocks are the problem. Now take the car on the road. If you are bouncing around a lot, and are affected by crosswinds, look into having the struts and shocks replaced.Beyond the "bounce test", a thorough visual inspection will show you if you need new struts or shocks. Good working struts and shocks are smooth and free from any fluid leaks. Any different and your struts and shocks have been compromised. One last check is in the status of your tires. If one or more have bald patches, your struts and shocks are giving in to excessive bounce.
Shock absorbers come in the form of McPherson Struts, coil-over shocks, or plain shock absorbers. Struts and coil-overs both have a coil spring suspension, and plain shock absorbers include separate leaf or coil spring.
Replacing worn struts or coil-overs can be dangerous due to spring pressure. Special equipment is required to safely compress the spring while the strut is being replaced. Plus, an alignment should be performed straight after.<
Replacing plain shock absorbers is much easier to do in a non-professional garage setting. All you need is a floor jack, jack stand and basic hand tools. Rear shocks on a more exposed vehicle, like a pickup truck, are much easier to replace. Sedans and other vehicles that require removal of parts to get at the top of the shock are more involved.