This workshop service and repair manual covers the Nuffield Universal 3 & 4 Series Tractors, produced from approximately 1954 to 1964. These British-engineered tractors, powered by BMC diesel, vaporizing oil, or petrol engines, were known for their robust construction and reliability, designed to meet the demanding needs of agricultural applications. With engine variants ranging from 2.55L to 3.77L and typically featuring manual transmissions with 4 or 6 forward gears, these machines offered dependable performance. The Nuffield Universal Series represented a significant advancement in tractor design for its time, contributing to the strength of the British agricultural machinery sector and earning accolades for their solid build. This comprehensive manual provides detailed, step-by-step instructions for the complete disassembly and reassembly of all major components and systems, including the engine, drivetrain, and electrical systems. It covers routine maintenance tasks, fluid changes, tune-ups, and in-depth repair procedures, making it an invaluable resource for owners, operators, mechanics, and restoration enthusiasts. The manual includes detailed illustrations and diagrams to aid in understanding and diagnosing issues, facilitating both do-it-yourself repairs and professional servicing. Its scope is designed to reduce reliance on costly professional servicing and empower users to maintain and repair their Nuffield tractors effectively.