Abstract: There is provided an improved dual side-by-side master cylinder having parallel pistons, one for each of two hydraulic sub-systems, and an actuator to move the pistons from a single applied force, e.g., a brake pedal, characterized by an improved structure for the actuator and its coacting rocking beam member for equalizing pressures in the two hydraulic sub-systems and for providing for takeover for direct transmission of force to one piston in the event of failure in the other sub-system.

Abstract: There is provided an improved disc brake caliper assembly characterized by a caliper body having first and second legs and a member joining them, and having a cylindrical bore extending through one of the legs and dimensioned to receive a cup-shape piston having a head portion and a piston skirt. A flanged second piston relatively movable in the cup-shaped piston is provided with an intermediate shoulder dimensioned to fit into said cylindrical bore and form therewith an annular chamber in which the skirt of the cup-shaped piston moves. A first fluid chamber is formed between the head of the second piston member and the inside closed end of the cup-shaped piston. A second isolated annular chamber is formed between the open end of the piston skirt and the shoulder. The flanged portion of the second piston member is secured by suitable fastening members to a flange receiving surface on the first leg. Fabrication of such a device is simplified, easier to machine and to assemble.