A fluid motor moves a lever to turn a power screw mounted for rotation by a pair of axially spaced bushings. External threads on the power screw engage internal threads on an actuator and slide or translate the actuator and a piston in a brake-applying direction. A spring moves the piston in the opposite direction to a rest position. A cap fits over a medial flange of the power screw and has a spline connection with the actuator to prevent rotation of the actuator. Four bolts connect the fluid motor mounting bracket and the cap to a caliper which slides on parallel pins fixed to a torque plate secured to a vehicle axle.