Abstract: A master cylinder having first and second compensating ports with a plurality of openings therein for rapidly allowing fluid communication between a reservoir and first and second chambers to maintain the master cylinder in a ready condition with respect to an input force in the development of pressurized fluid to effect a brake application.

Abstract: A one piece seal (42) having a resilient body (100) with a peripheral surface (102) on which first and second ribs (104 and 106) engage a housing (19) to establish static seals to prevent environmental air from entering a control chamber (22) and an inner surface (114) with first and second dynamic seals (120 and 128) located adjacent first and second bearing lands (116 and 118). The first and second dynamic seals (120 and 128) which surround a movable projection (38) flex to allow the projection (38) relatively radial movement while the bearing lands (116 and 118) retain the projection (38) in axial alignment during lateral movement of the wall (24).