Oh, and the valve handle is inside the cab, while the actual valve will be on the underside of the cabs sheetmetal in plain sight, where you can inspect it........the valve and its handle are brass as i recall, and the handle and the actual valve are keyed alike with either splines or a "D" shaped shaft to mate with the valve handle, then secured with a screw......the shaft or handle may have worn, to where the handle itself is turning upon the actual valve assembly.....