Abstract: A wheel disc brake system for a motor vehicle connected to a brake fluid pressure system that includes a pressure relief apparatus for moving the inner piston of the wheel brake back into the brake housing piston chamber by an Allen wrench insert into an axial tool hole at the front face of the inner piston accessed through the axial oil hole of the outer piston. Rotation of the wrench rotates the inner piston along the actuating screw member in the brake housing and so moves the inner piston away from the outer piston so that the outer piston can be easily pushed into the brake housing and new brake pads mounted to the calipers. Reverse rotation of the wrench pulls the inner and outer pistons back into operational position. The invention also includes a cylindrical nose extending from the inner piston having at least one seal to defend the tapered actuating areas of the inner and outer pistons from contamination through the oil hole of the outer piston.