Abstract: A master cylinder includes a valve that is slidably mounted in a movable piston means for limited axial movement therein between a closed position wherein the valve is sealingly engaged with the piston and an open position wherein a gap is maintained between the valve and the piston. The valve includes a passage for providing fluid communication between the supply chamber and the pressure chamber when the valve is in the open position. An orifice in the piston limits the flow of fluid from the pressure chamber to the supply chamber at least during the limited movement of the valve from the open position to closed position. An overflow arrangement on the piston is responsive to movement of the piston against the bias of a biasing device for establishing fluid communication between the passage and the supply chamber only when the valve is in the closed position.