Brake master cylinders take the pressure provided by a driver's foot on the brake pedal and convert it to hydraulic pressure which then operates the calipers and wheel cylinders. Clutch master cylinders work in a similar fashion by applying the force to a throw-out bearing which disengages the clutch from the engine's flywheel. Master cylinders typically have a reservoir on top which holds hydraulic fluid (brake / clutch fluid) and prevents air from entering the hydraulic system.
As with most components in a hydraulic system, when a master cylinder begins to fail it will mean big trouble if not fixed immediately. Leaks will result in the system not performing adequately which will lead to lack or absence of braking power, or the clutch not disengaging when pressure is applied to the pedal. These sorts of issues are very dangerous and should be repaired right away!
Replacing a mastery cylinder requires knowledge of hydraulic systems and often times ABS (Anti-lock Brake System) as well. Considering the nature of thse systems, the importance in their proper opration on a vehicle, and the cost of mistakes, it is best to leave these jobs to the professionals!
We have a excellent selection of quality master cylinders from the following manufacturers: