A pump chuck for connection with a valve stem of a tire valve is disclosed. The pump chuck comprises a body having a first bore, a second bore, a third bore and a passageway connecting the first bore and the third bore therethrough, a pivot clip pivotally mounted on the body and having a plurality of threads on one end and a depression on a bottom surface, a spring compressed between the pivot clip and the body, a rubber seal housed inside the first bore of the body, an end cap mounted on the top surface of the body above the first bore, and a connector housed inside the third bore of the body to connect a hose from a tire pump. The contact of the rubber seal against the valve stem affects an air tight seal.