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Clutch slave cylinder with integrated clutch release bearing
The brake fluid reservoir with separate chamber is used to supply the system.
Depressing the clutch pedal builds up pressure in the clutch master cylinder and operates the release bearing integrated in the clutch slave cylinder.
The clutch operation system is self-ventilating. The components are arranged in such a way that small amounts of air trapped in the system are removed automatically.
The clutch pedal operation is affected by damage in that greater pedal effort is required. The pedal also returns to its starting position very slowly.
The advantages of a hydraulic clutch are:
- automatic adjustment
- low operating force required
- low wear
Reservoir
The brake fluid reservoir supplies both the hydraulic clutch system and the brake system with brake fluid.
The hydraulic clutch system and the brake system are separate inside the brake fluid reservoir. In the event of any leaks in the hydraulic clutch system the brake system remains fully operative.
Clutch Master Cylinder
The clutch master cylinder generates the system pressure for operating the clutch.
If the clutch pedal is pushed down the piston rod moves the clutch master cylinder piston. The hydraulic fluid in the clutch master cylinder is put under pressure and fed through the pressure pipe to the clutch slave cylinder.
Slave Cylinder - Clutch
The central clutch slave cylinder is equipped with an integral release bearing and is attached to the clutch bell housing with three bolts. The release bearing is an interference fit on the clutch slave cylinder.
The hydraulic fluid displaced by the piston in the clutch master cylinder moves the piston in the clutch slave cylinder; this piston then moves the release bearing in an axial direction. The release bearing presses against the tongues of the diaphragm spring with the inner bearing ring. This breaks the friction contact between the clutch disc and the flywheel.
When the clutch pedal is released the diaphragm spring presses the piston in the slave cylinder back to its starting position. The spring induced adherence between the clutch disc and the flywheel is created again.
Pre-load valve (vehicles built up to 08/1999)
The pre-load valve is located at the entrance to the clutch slave cylinder (high-pressure line). The valve maintains a constant pressure of 1 bar in the slave cylinder after the clutch pedal is released. This pre-load keeps the release bearing pressed against the diaphragm spring with a constant pressure of 80 - 100 N. When the clutch pedal is not depressed, the hydraulic system between the master cylinder and the slave cylinder is pressureless, as a result of which no vibrations are transmitted to the clutch pedal and no adjustments to the clutch are necessary.
CAUTION:The pre-load valve must be tightened to the specified torque.
If the pre-load valve is not tightened to the specified torque it will be damaged. As a result of this, more force is required to depress the clutch pedal and the pedal is slow to return to its initial position.
Pre-load valve (vehicles built 08/1999 onwards)
The pre-load valve is discontinued, the pre-load is produced by a spring.
Clutch operating mechanism components (vehicles built up to 08/1999)
