Abstract: An apparatus and method of applying an expandable member, such as an O-ring, to a part to from an installed part. The apparatus and method comprise a piston slidably positioned within a housing with a slidable sleeve interposed between the housing and the piston. The piston has an expandable member engagement surface on a leading end thereof. During operation, the expandable member is transferred from a holder to the exterior surface of the slidable sleeve. The slidable sleeve is then positioned sleeve about the part and relative movement of the housing with respect to the sleeve, transfers the expandable member from the sleeve and onto the part.