Abstract: A self-energizing brake of the disc/rotor or rim type is disclosed which includes opposed rocker arms attached to a frame by a bolt or the like. The rocker arms support brake pads adjacent the disc/rotor or rim. Cantilever arms on each of said rocker arms extend opposite the brake pads and are connected to a pressure actuated cable. The rocker arms also terminate in a housing which is rotatable about the bolt. The housing encloses unitary helical ridges which mate with helical ridges on a cylinder fixedly secured to the frame by the bolt. The housing is axially movable relative to the bolt. The housing is sealed about the bolt by O-rings and contains a lubricant such as grease. When force is applied to the cable, the pads contact the rotating rim. Such rotation results in movement of the housing in an axial and rotational direction which, due to the interaction of the helical ridges, multiplies the force exerted on the rim by the brake pads.