Abstract: A new disc brake assembly tool for providing an easy means for positioning a piston into the piston cylinder of a caliper to provided proper clearance so that a disc brake pad may be installed. The inventive device includes a base having an elongate center 1t portion, an arm portion, and a foot portion. The arm and foot portions are extended substantially perpendicular from the center portion and are spaced apart from one another. A mount member is coupled to the terminal end of the arm portion. The mount member has a mount bore extending therethrough. Inserted through the mount bore is a tubular sleeve having a threaded lumen. the sleeve being positionable within the mount bore between an extended position and a retracted position. The proximal end of the sleeve has a radial flange outwardly extending therefrom.