Abstract: A hydraulic elevator jack having a cylinder, a cylinder head, a plunger, and an improved seal assembly disposed between the cylinder head and plunger. The seal assembly includes a compartmentalized sleeve which axially separates a wear ring and a sealing function, with the wear ring being disposed closer to the cylinder, i.e., on the oil or pressure side of the cylinder head, than the sealing function. The wear ring is discontinuous, having at least first and second spaced ends, providing improved distribution of load on the wear ring while reducing drag and tendency of the wear ring to bind. The sealing function includes at least one O-ring energizing seal having a main body portion, and a discontinuous, elastomeric, solid body O-ring disposed in a cavity defined by the body portion. The O-ring is preferably centered relative to the axial dimension of a sealing surface of the main body portion.