Hyundai 31N4-40651 Swivel Joint Seal Kit

The swivel joint (center joint / turning joint) provides a rotating hydraulic connection between the excavator upper structure and undercarriage, channeling pressurized fluid to the travel motors. This seal kit restores sealing performance at the rotary manifold interface, eliminating internal leakage that causes travel power loss and overheating. Kit includes precision-molded piston seals, rod seals, wear rings, O-rings, and backup rings engineered to OEM groove dimensions. Materials comprise high-durometer NBR (Nitrile Butadiene Rubber) for primary sealing, PTFE anti-extrusion rings for high-pressure stability, and polyurethane wear guides for contamination resistance. Designed for continuous operation at 35 MPa system pressure and -30°C to +120°C temperature range. Compatible with mineral hydraulic oils and water-glycol fluids. Direct replacement for Hyundai OEM part numbers 31N4-40651 and 31N4-40951.