The Farmall 504 is a versatile tractor that served the agricultural community from approximately 1961 to 1967. As part of the '4' series, the Farmall 504 represented significant progress in farm tractor engineering, offering reliable performance and robust construction. Available with either a gasoline or a diesel engine, including the BD-154 diesel, it provided ample power for a wide range of farm tasks, with gasoline variants typically offering around 40-45 PTO horsepower and diesel models around 45-50 PTO horsepower. Its design incorporated features like a 10-speed constant mesh transmission, often paired with an optional Torque Amplifier for enhanced operational flexibility, making it a capable workhorse for its era. This comprehensive workshop service repair manual in English is designed to be an indispensable resource for farm owners, mechanics, and technicians working on the Farmall 504. It covers all essential aspects of maintenance, servicing, and repair, including detailed procedures for the engine, cooling system, fuel system (diesel and gasoline), ignition system, clutch, transmission, torque amplifier, final drive, differential, brakes, steering, hydraulic system, power take-off (PTO), and electrical system. The manual provides step-by-step instructions, troubleshooting guides, adjustment procedures, and complete overhaul instructions, all based on manufacturer specifications and including helpful diagrams for clarity.