A-3901517M1-AI Expansion Valve (block type)One New Aftermarket Replacement Block Type Expansion Valve Fits Massey Ferguson, Fits Case IH, Fits John Deere, and More This block type expansion valve is a direct fit replacement for the air conditioning system on a wide range of agricultural tractors, combines, forage harvesters, sprayers, and construction equipment. The expansion valve regulates refrigerant flow, reducing pressure so the refrigerant transitions from liquid to vapor and produces