The figure displays the vacuum clutch system. This kind of clutch works by using the existing vacuum from the engine manifold to function the clutch. The vacuum clutch consists of a reservoir, non-return valve, vacuum cylinder with piston, and solenoid valve.  Slipping Clutch: This can be the most typical symptom. https://tituskzpfu.blogpixi.com/33296425/5-simple-techniques-for-clutch-plate