When the operator presses the clutch pedal, the clutch release mechanism pulls or pushes on the clutch release lever or fork (Figure 9-8). The fork moves the release bearing into the center of the pressure plate, causing the pressure plate to pull away from the clutch disc releasing the disc from the flywheel. The engine crankshaft can then turn without turning the clutch disc and transmission input shaft.
When the operator releases the clutch pedal, spring pressure inside the pressure plate pushes forward on the clutch disc. This action locks the flywheel, the clutch disc, the pressure plate, and the transmission input shaft together. The engine again rotates the transmission input shaft, the transmission gears, the drive train, and the wheels of the vehicle.
Figure 9-8 — Clutch operation.