Shocks and struts are part of the suspension system of a vehicle. They serve two main functions: they provide a smooth and comfortable ride and they keep the wheels on the road at all times. Both shocks and struts combine a spring and a damping unit. An automotive coil spring has an uncompressed length, a static compressed length as the vehicle sits on the road, and changes in the spring length as the wheel hits bumps in the road. If the suspension system was just springs the car would bounce along as it hits bumps in the road. It would be uncomfortable and hard to control.
A damper is a sealed cylinder with a rod that moves a piston up and down as the wheel moves up and down. The cylinder contains hydraulic fluid that is forced through holes and valves in the piston. These holes and valves are carefully designed to properly control the wheel's speed.
The damper wears slowly as the miles pile up, and it can't control the wheel as well as new units. It's hard to tell if new struts or shocks are needed because the change is so gradual it's easy to miss. For a car used hard on a bumpy dirt road, the shocks or struts may need replacement in 40,000 or 50,000 miles. Cars used in a more normal environment can expect more like 70,000 to 90,000 miles.
There are several signs that indicate the need for new shocks or struts.
- The front of the car dives with heavy braking and the rear squats with hard acceleration.
- When driving at highway speeds on smooth roads there are small up and down movements.
- Excessive swaying and a wobbly feeling as the car turns.
- The tires take a long time to settle down after hitting a bump.
- There is leaking hydraulic fluid on the body of the shock or strut.
Have you noticed any of these? If you need your shocks or struts replaced, we invite you to bring your vehicle to Harrell Automotive today!