Master cylinder

A master cylinder ( 10 ) for a vehicle hydraulic brake system has a housing ( 12 ), which has a bore ( 14 ), which extends along a longitudinal axis (A) and is sealingly closed at one end by an end wall forming part of the housing ( 12 ) of the master cylinder ( 10 ) and at the other, opposite end by a closure element ( 16 ). A piston ( 18 ), which is guided in the bore ( 14 ), extends in a sealing and axially displaceable manner through the closure element ( 16 ). A central valve ( 20 ) is formed on the piston ( 18 ) and enables a fluid connection between a fluid reservoir and a pressure chamber ( 28 ) delimited in the bore ( 14 ) by the end wall and the piston ( 18 ) and, in the non-actuated state of the piston ( 18 ), is held in open position by an abutment component ( 34 ) acting upon the closure element ( 16 ). The closure element ( 16 ) is formed by two annular, axially mutually adjoining parts ( 42, 44 ), which are releasably connected to one another and of which the first part ( 42 ) facing the bore ( 14 ) is made of an elastomer material and the second part ( 44 ) remote from the bore ( 14 ) is made of a rigid material. For easy and reliable assembly, the part ( 44 ) of the closure element ( 16 ) remote from the bore ( 14 ) has at least two compliant detent arms ( 57 ), which interact with a detent groove ( 66 ) formed in the housing ( 12 ).