The figure reveals the vacuum clutch system. This sort of clutch utilizes the present vacuum inside the engine manifold to operate the clutch. The vacuum clutch consists of a reservoir, non-return valve, vacuum cylinder with piston, and solenoid valve.  With the motor vehicle idling, hear for just a growling noise https://clutch-kereta86418.blogolenta.com/29951104/new-step-by-step-map-for-clutch-plate