Abstract: A sealing assembly especially adapted for high pressure hydraulic applications includes a circumferentially compressible seal ring having stepped overlapping ends and a resilient expander, preferably of oval cross-section, which assists in urging the compressed seal ring into sealing communication with the thus sealed surfaces. The seal ring is manufactured with an oversized closed gap condition from a filled synthetic material having a modulus of elasticity sufficient to permit compression thereof when the seal ring is installed between the thus sealed surfaces. The ring may optionally include a secondary resilient sealing member positioned between the axial, internal surfaces of the steps.