Clutch: Description and Operation
System Overview
Power is transmitted from the engine to the gearbox via a clutch. This clutch consists of a dry plate and a pressure plate of diaphragm spring type. Clutch operation is hydraulic.
Clutch
Power is transmitted from the flywheel on the engine to the input shaft in the gearbox via a driven plate. This power is transmitted by the pressure plate, which is bolted to the flywheel, forcing the friction surface of the driven plate against the flywheel.
The diaphragm spring on the plate is linked to the input shaft by a splined connection. When the release bearing on the slave cylinder presses on the "fingers" of the diaphragm, these function as levers and release the clamping force of the pressure plate from the driven plate and flywheel. This disengages the engine from the gearbox.
Clutch Operation
Clutch operation is hydraulic and entirely self-adjusting. The mechanism consists of a master cylinder (1), a clutch pipe (2) and a slave cylinder (3).
The master cylinder is mounted in the bulkhead wall and linked to the clutch pedal by a piston. The slave cylinder is an integrated unit mounted in the clutch housing and consists of a cylinder housing (4), a split piston (5) and a fixed release bearing (6). The slave cylinder cannot be dismantled. The hydraulic pressure from the master cylinder is led in and presses on the seal which then forces the piston and release bearing against the pressure plate. There is a spring mounted between the cylinder housing and release bearing which ensures that the release bearing is always held against the pressure plate, reducing play in the clutch pedal.
In order to prevent dirt from reaching sensitive parts of pistons and seals, a rubber gaiter is mounted between the cylinder and release bearing.
A hydraulic line links the master cylinder and the slave cylinder's damper pipe (to reduce pedal vibration) and has a quick-release coupling at each end. The lower quick-release coupling, to the slave cylinder, has a bleed nipple.