Hydraulic release systems give greater flexibility than cable or mechanical mechanisms. The master cylinder is mounted on the firewall or can be incorporated in the pedal and is connected to the slave cylinder via a flexible hose. Flexible hoses are used to accommodate any relative movement between the body and engine/transmission. The concentric slave cylinder eliminates the need for a clutch release lever by combining the release bearing and slave cylinder on the gear box front bearing retainer. As the friction material on the driven disc wears, the release mechanism is repositioned forcing the excess fluid to the master cylinder reservoir. By design, the efficiency of the release system is achieved by a small bore diameter master cylinder with a larger bore slave cylinder.

There are two types of master cylinder:

1. Compensating Port Design
When the clutch pedal is not in use the piston in the master cylinder exposes a small hole to the reservoir. As the clutch pedal is depressed, the seal/cup passes the compensating hole effectively closing the port, and then the remaining fluid actuates the slave cylinder.

2. Centre Valve Design
When the clutch pedal is not in use, the piston in the master cylinder retracts to open the port in the base of the cylinder. As the clutch pedal is depressed, the centre valve is closed and the remaining fluid actuates the slave cylinder.

Clutch Master Cylinders
Direct fit kits are supplied with the correct bearing or concentric slave cylinders designed for use with the OE clutch master cylinder.