LuK Master Cylinder

LuK Master Cylinder

The master cylinder converts pedal force into hydraulic pressure

Product description:

The master cylinder is a component of the clutch release system that delivers the necessary pressure build-up in the hydraulic system. It is usually mounted to the front bulkhead or to the pedal holder with bolts or a bayonet lock. The master cylinder’s piston rod is connected directly to the clutch pedal inside the vehicle.

The master cylinder consists of a housing, a piston with piston rod and a pair of seals (primary and secondary seal). It has a hydraulic port, normally a quick connector, for the pressure line through which it is connected to the slave cylinder. On some models the screw connector commonly used on brake systems can still be found. The master cylinder is connected to the hydraulic fluid circuit. In many cases, it is connected to the brake fluid reservoir via a hose; but there are also solutions providing a separate reservoir for the clutch cylinder. The primary seal separates the reservoir from the hydraulic chamber, thus generating the pressure required to actuate the clutch. The secondary seal seals up the low-pressure chamber of the reservoir against its environment. With the clutch pedal released, a spring at the pedal or in the master cylinder pushes the piston back entirely. In this position, the connection between the reservoir and the pressure chamber is open which allows the air trapped in the system to escape and liquid to enter. The self-adjusting mechanism of the hydraulic system is used.


  • Weight optimized
  • Heat resistant
  • Long service life
  • A compact system
  • Requires little space, delivers maximum performance
  • Less susceptible to external influences
  • Requires low pedal force

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