Abstract: A quick release valve for a vehicle braking system has an inlet port, an outlet port for connection to a brake actuator, and an exhaust port closed during operation of the actuator by a working area of a diaphragm. A support area of the diaphragm surrounding the area has peripheral indents with re-entrant edge portions. Reduction of the support area by formation of the indents lessens noise produced by the valve during exhausting after operation of the brake actuator.

Abstract: The invention relates to master cylinder and actuator assemblies in which a push rod connected to the actuator extends forwardly through a vehicle mounting member and is engageable at its forward end with a piston, there normally being a clearance between the push rod and the piston in their inoperative positions. Such assemblies suffer from the disadvantage that a desired working clearance is difficult to attain due to manufacturing tolerances. Embodiments of the present invention overcome that disadvantage and provide an assembly which includes a lateral projection (10) on the push rod (5), which projection limits rearward movement of the push rod relative to the mounting member (3).