Abstract: A master cylinder (12) and pneumatic brake booster (10) assembly for use in a motor vehicle. The pneumatic brake booster (10) has a casing (15) fastened to a wall (16) which separates a cabin (H) from a front compartment (C) of the motor vehicle. The pneumatic brake booster (10) is actuated by control rod (18) having a rear end which is connected to a brake pedal located in the cabin (H). The master cylinder (12) has a body (20) formed with at least one flange (22) for fastening the master cylinder (12) onto the front wall of the casing (15). An aggressive element (26) extends from the body (20) and engages the casing (15) on rotation of the master cylinder (12) in response to a torque being applied to the master cylinder (12). Engagement of the aggressive element (26) with the casing (15) will attenuate the communication of the torque into the control (18).

Abstract: A master cylinder comprising a body (4) pierced with a bore (5) closed on a first side by an end (6) and on a second side by a piston (7). The piston (7) slides in the bore (5) to delimit a pressure chamber (8). The pressure chamber (8) is connected by a pressure pipe (12) to at least one brake motor through an outlet (11) therein. The chamber (8) and the pressure pipe (12) together delimiting a working volume filled with a hydraulic fluid. The working volume is partially delimited by a leak-off device (19) which is responsive to an impact to selectively allow hydraulic fluid to leak off toward the outside of the working volume.

Abstract: An assembly of a pneumatic brake booster (100) and a master cylinder (200) for a motor vehicle. The pneumatic brake booster (100) has a casing (20) fixed to the bulkhead (10) of the vehicle. The casing is divided in leaktight fashion by a movable wall structure (22) into a front chamber (24) permanently connected to a source of partial vacuum and a rear chamber (26) connected selectively to the front chamber (24) or to the atmosphere by a valve means (16). The valve means (16) is actuated by a control rod (14) for actuating a push rod (28). The master cylinder (200) has a body (21) formed with at least first and second flanges (38, 38'; 40, 40'). The first and second flanges (38, 38'; 40, 40') interact with corresponding screws and nuts to fix the body (21) with the casing (20) of the booster (100). The body (21) has a bore (34) for slidingly receiving at least one piston (32) which is actuated by the push rod (28) of the brake booster (200).