Abstract: A double diaphragm pump includes a connecting shaft for interconnecting the opposed diaphragms mounted in the pump body for reciprocal movement relatively thereof and a pilot valve sleeve telescoped over the shaft and movable axially in response to movement of the connecting shaft and having a plurality of axially directed circumferentially disposed recesses thereon for fluid transfer through the pilot valve cavity. A spool valve assembly is also carried by the body in a cavity which is in selected fluid communication with a source of air pressure, the pilot valve, the atmosphere and the pressure chambers of the pump. The pilot valve sleeve also has at least one projecting annular rib which engages the usual O-rings of the cavity in which the connecting rods and pilot valve sleeve reciprocate for assisting movement past the O-rings in response to pressure from the spool valve.