Abstract: The assembly comprises a flexible bulb 12 defining a pumping chamber 14 and secured at opposite ends by bands 34 to inlet and outlet housings 26. An inlet check valve 18 is supported by an inlet valve wall 38, which is, in turn, supported in a recess 36 in the inlet housing, to control fuel flow to the pumping chamber 14 while preventing reverse fuel flow out of the pumping chamber 14. An outlet check valve 22 is supported by an outlet valve wall 52 which is, in turn, supported in a recess 36 in the outlet housing for controlling fuel flow from the pumping chamber 14 while preventing reverse flow from the outlet housing into the pumping chamber 14. The assembly is characterized by a pressure relief valve, generally shown at 24, disposed between the inlet and the pumping chamber 14 for allowing fuel under a predetermined pressure in the pumping chamber 14 to reverse flow into the inlet. The opposite ends differ only by the inlet valve wall 38 supporting the relief valve 24.