Another similar front suspension system is called the "hydraulic shock strut." This strut serves as a shock absorber and replaces the upper control arm. The coil spring, however, is located between the lower control arm and the body structure instead of being mounted directly on the strut.
Shock Absorber StrutsA strut is a structural piece designed to resist pressure in the direction of its length. On typical "McPherson Strut" use, the shock absorber is built into the strut. Most shock absorber struts are hydraulic units. Like the hydraulic shock struts, faulty units must be replaced as an assembly. Shock absorbers and struts do more than just provide a comfortable ride. Their most important function is to influence the control and handling characteristics of your vehicle. Without them, a vehicle would continually bounce and bound down the road, making driving extremely difficult. Shocks and struts are designed to help keep your tires on the road. They control the action of the spring to resist bottoming out like when you hit a pothole and keep the movement of the springs under control when they rebound.
Shock Absorber Struts