There is a hydraulic pump in the engine compartment, and a valve bolted to the rear axle with a lever to the torshion bar. As the car lowers the lever moves and alows fluid to flow. The rear shocks are hydraulic struts are connected to this fluid and are dampened by a gas filled spheres. The shocks rarely fail unless they leak, the spheres do go bad. The symptom is either very spongey or rough rtide