This hydraulic tank check valve is an original AGCO component that controls the direction of fluid flow within the tractor's hydraulic reservoir. It mounts in the tank outlet or return port and prevents backflow from the supply line into the tank when the pump is not running. A worn or stuck check valve allows fluid to drain back, causing a delay in hydraulic response at startup and potential cavitation in the pump. The valve's seat and poppet are machined to the same geometry as the original assembly, ensuring the cracking pressure matches the system's design specification. On reinstallation, verify the sealing O-ring is clean and seated properly to prevent external leakage.