The Massey Ferguson MF 3115, MF 3120, MF 3125, and MF 3140 tractors represent a robust line of agricultural machinery, primarily produced in the late 1980s and early 1990s. These tractors, powered by typically 4-cylinder diesel engines ranging from approximately 60 to 90 horsepower, feature direct injection fuel systems, with many higher horsepower variants incorporating turbocharging and intercooling. Their engineering emphasizes reliability and durability, hallmarks of the Massey Ferguson brand's long heritage in agricultural equipment. These models are equipped with versatile transmissions, often a 12-speed synchronized gearbox with powershift capabilities, designed to handle a wide array of farming tasks efficiently. This comprehensive Service and Repair Manual provides in-depth technical information for the Massey Ferguson MF 3115, MF 3120, MF 3125, and MF 3140 tractors. It covers all essential systems, including the engine, transmission, hydraulics, electrical system, steering, brakes, chassis, PTO, front axle, and operator station. The manual details routine maintenance procedures, extensive troubleshooting guides, component replacement and rebuild instructions, and calibration procedures. With clear diagrams, schematics, and torque specifications, this resource is indispensable for owners, operators, and professional technicians seeking to maintain, diagnose, and repair these tractors, ensuring optimal performance and longevity.