Abstract: Tandem master cylinder comprises primary and secondary pistons (3,4) moved apart by means of two springs (9, 10). Only one (9) of the two springs is prestressed in the rest position of the piston. The pressures in the primary 6 and secondary 7 chambers are thus very rapidly made similar to each other, without it being necessary to mount the springs in a cage of adjustable length.

Abstract: The brake regulator for a motor vehicle, comprises a body (1) pierced with a bore in which an annular gasket (7) defines first and second chambers (2, 3), of which the first (2) is connected to the circuit of a master cylinder and the second (3) to at least one brake motor, and a valve-forming piston (8) movable in axial translational motion in an annular spacer (18) bearing against the annular gasket (7). The piston (8) has a diameter larger than that of the central orifice of the annular gasket (7) forming a valve seat, and is equipped with a pusher (9) which passes through the annular gasket (7) and the first chamber (2) and projects sealingly from the body (1). The assembly consisting of the annular gasket (7) and of the annular spacer (18) is mounted to be movable in axial translational motion, and the second chamber (3) also comprises an elastic mechanism (6) confined between the annular spacer (18) and the bottom of the bore.

Abstract: The invention relates to a wheel cylinder for a drum brake, comprising a body (2) provided with a longitudinal bore, two pistons (4,6) sliding in opposite directions outwards in the bore under the action of a pressurized fluid introduced between the pistons against the return springs of the shoes of the brake, and a mechanism limiting the return travel of the pistons when the pressure is released. According to the invention, the mechanism limiting the travel consists of two resilient rings (16, 18), at the outer periphery of each of which a friction mechanism (20, 22) is disposed, and which are disposed, respectively, in an annular groove (24, 26) made in each of the pistons so as to provide a specific axial clearance (d) between a radial wall of the groove and the adjacent side of an assembly consisting of the resilient ring and the friction mechanism, this assembly being provided in order to resist the return springs of the brake shoes in a drum brake.