This seal kit replaces the gaskets and seals inside the hydraulic coupler on the host tractor. It sits between the coupler body and the hose fitting, preventing fluid leakage at the connection point. A worn seal in this location causes external oil loss and can allow air ingress into the hydraulic loop, leading to spongy implement response. The kit is manufactured by AGCO and is dimensioned to match the original coupler bore and seal groove geometry, so the sealing faces align correctly without additional shimming. On installation, clean the coupler bore and ensure the mating surfaces are free of debris before seating the new seals.