Abstract: A plug for a threaded port is formed of resilient elastomeric material and has upper and lower ends. A smooth non-threaded outer cylindrical wall is disposed between the ends. The outer cylindrical wall has an outer diameter sufficient to frictionally engage the threads of the port. An outwardly protruding collar is disposed between the upper end and the outer cylindrical wall. An annular bead is integrally formed on the collar and is adapted to sealingly engage an inner peripheral surface of the port.

Abstract: A holddown pin mechanism for hydraulic power units has a cylindrical flat base washer having a central opening and opposite sides, a plurality of spaced elongated holddown pins have one end rigidly secured to one side of said base washer and an outer end. The pins extend outwardly at right angles from the side of said washer to which they are secured. The holddown pin mechanism is placed in a hydraulic cylinder block having a center bore, with the pins extending into holes in the block. A guide member on a shaft extending through the block engages the free ends of the pins.