Shock absorbers and struts influence the control and handling characteristics of your vehicle. They work in conjunction with the vehicle’s springs to dampen the bouncing motion of the vehicle as affected by road conditions. The energy is absorbed as a piston inside the shock pushes against hydraulic fluid. This restricts the rebounding movement of the springs.
You can tell a great deal about performance of shock absorbers by simply feeling your car's suspension as you drive.
Shock and Strut Warning Signs:
1. Excessive Bouncing
Coil springs are part of your vehicle's suspension system. If your vehicle is designed with shocks, the coil springs are mounted between the wheels and the frame of the vehicle. Struts, on the other hand, are essentially a coil spring and shock absorber all in one piece. When you drive over a bump, your car bounces on the coil springs, regardless of whether you have shocks or struts. The shock absorbers in both cases keep your car from bouncing nonstop.
2. Nose Dives/Rear End Squats Dipping
Your car should be steady and stable at all times – whether you are braking, accelerating, or turning – so that you can maintain control as you drive. Shock and struts help keep the car steady.
When braking, if the front end of your vehicle, otherwise known as the nose, of your car dives, it is an indication that your shocks and struts need to be replaced, or at least evaluated. Another sign that your shocks or struts require service is if the rear end of your vehicle “squats” when you accelerate. Additionally, if you make a turn and the vehicle dips drastically to one side, your shocks or struts may need to be replaced.
3. Tire "Cupping"
If the struts or shocks on your vehicle are bad, the tires will literally bounce up and down as you drive. Each time the tires hit the ground, bits of rubber can get scraped off. This is commonly referred to as “cupping” or “scalloping.” So instead of having a consistent treadwear pattern across the tire, you might have some tread, a smooth patch, some tread, a smooth patch, and so on. This is because the holes left by the missing rubber tend to get smoothed over as you drive.