The David Brown 1390 is a robust tractor model, produced through the 1970s and early 1980s, renowned for its reliability and engineering. As part of the 1300 series, it represents a significant development in agricultural machinery, offering dependable performance for a variety of farm tasks. Its design emphasizes practicality and durability, making it a valued asset for owners and operators in the agricultural sector. The David Brown heritage is rooted in quality manufacturing, contributing to the enduring reputation of models like the 1390 for their operational resilience. This Workshop Service Manual (WSM) provides comprehensive guidance for all service and repair jobs, as well as routine maintenance for the David Brown 1390. It covers detailed procedures for the engine, fuel, cooling, lubrication, transmission, drivetrain, braking, steering, electrical, and hydraulic systems. The manual includes step-by-step instructions, troubleshooting guides, overhaul procedures, calibration and adjustment information, and detailed electrical wiring diagrams, all supported by clear illustrations. Its purpose is to empower tractor owners, farm mechanics, and agricultural workshops with the knowledge to perform maintenance and repairs efficiently, ensuring cost savings and operational independence.