Abstract: A bag control mechanism (or center mechanism) for a tire press in which cross flow of curing medium from the inlet to the outlet is prevented. The center mechanism includes a cylindrical casing having a piston rod reciprocable therein, and an annular fluid distribution member comprising a hub and a distribution cap at the upper end of the casing. The hub has a central bore of larger diameter than that of the piston rod, and inlet and outlet passageways for a curing medium, on opposite sides of the bore. The hub may also have passageways which permit sensing of a condition such as temperature within the tire press. The hub also has lateral passageways from the bore to the outlet passageway, and from the outside surface of the hub to the outlet passageway. The inlet passageway is separated from the bore by a portion of the hub's body. The distribution cap has an opening or passageway aligned with the inlet passageway of the hub, and a cut-out portion aligned with the outlet passageway of the hub.