Abstract: A caliper type disc brake actuated by threaded members of a screw and nut assembly in which one of the members is axially movable but held against rotation and the other threaded member is rotatble relative to the caliper. The rotatable member is mounted for the application of force against the caliper during braking. Clamping force is applied to a friction lining carrier upon rotation of the rotatable threaded member in one direction. The threads of the threaded member have a helix angle and shape to cause overhauling rotation of the rotatable threaded member in the opposite direction upon release of the clamping force on the friction lining carrier for automatic return of the brake parts from a braking position to a position away from the disc.