This workshop service manual covers the David Brown 1390 Tractor, a robust and reliable piece of agricultural machinery known for its enduring performance. David Brown tractors have a long-standing reputation for quality and durability in demanding farming environments, and the 1390, likely produced in the late 1970s to mid-1980s, represents a significant advancement in tractor design for its era. This manual is designed to provide comprehensive technical information for maintaining and repairing this esteemed model, ensuring its continued operational efficiency. The purpose of this manual is to offer detailed guidance for mechanical technicians, agricultural mechanics, and skilled owners. It encompasses a wide range of topics, including routine maintenance, comprehensive repair and overhaul procedures for all major systems such as the engine, fuel, electrical, transmission, drivetrain, hydraulics, steering, and brakes. The manual also covers bodywork, troubleshooting common and uncommon issues, and provides specific instructions for proprietary components, emphasizing safety with clear WARNING, CAUTION, and NOTE statements. It includes references to special tool numbers and is written in English for clarity and ease of use.