An apparatus for removing and installing a valve stem into an opening defined by a rim. An inoperable valve stem is removed from the rim from the outside of the rim, and an operable valve stem is installed into the rim from the outside of the rim, thus avoiding separating the tire side wall from the rim during removal and installation of the valve stem. The inserter comprises a tool using pressurized fluid to force a piston and piston rod out of a chamber. A conventional valve stem is forced through the inserter and through the opening defined by a wheel or rim.