Abstract: A high pressure, self-sealing and self-lubricating, reciprocating pump having a pair of uniformly thin wall, radially resilient, cylinders extending in parallel into adjacent cavities of a pump housing. Pistons, driven by a wobble plate and slidable in the cylinders, are of uniform diameter along their entire lengths of insertion in the cylinders on the compression stroke. The outer surfaces of the cylinders form annular spaces in the cavities which communicate with pressure chambers in a manifold operatively connected to the pump housing. Ball check valves within the manifold control the fluid flow at the inlet and outlet thereof. Bushings positioned around the cylinders intermediate the ends thereof provide resistance to skewing forces by the wobble plate. Pressure changes due to compression and suction in the pump causes the thin wall cylinder to collapse and expand about their respective pistons forming thereby a high pressure seal during compression, and a self-lubricating cylinder during suction.