Abstract: A disc brake for operation on the pinion shaft of a motor vehicle has a disc assembly consisting of two parallel discs spaced from each other by a pattern of ribs. Spaces between the ribs provide ventilating passages into which air enters and circulates through the disc and ports extending through the discs on the forward and rearward sides. The disc assembly is keyed to the pinion gear shaft and bolted to the yoke of the shaft in driving relationship with the pinion shaft thereby to rotate with the driving component. A bracket bolted to the differential housing supports friction surfaced braking elements on opposite faces of the disc assembly and a remotely controlled hydraulic actuated piston provides the force which draws the braking elements into engagement with the disc assembly.