This manual provides comprehensive service and maintenance information for the David Brown CAD4 30 engine, applicable to all models and configurations. Designed for robust performance and reliability, the CAD4 30 engine represents a significant engineering achievement, built to withstand demanding operational environments. Its robust construction and efficient design ensure dependable power delivery, making it a trusted choice for various applications. The purpose of this workshop repair manual is to equip owners, mechanics, and technicians with the necessary knowledge to maintain, troubleshoot, and repair the David Brown CAD4 30 engine effectively. It covers essential maintenance procedures, detailed troubleshooting guides, and technical specifications, all aimed at preserving the engine's optimal performance and longevity. By following the instructions within this manual, users can ensure the continued reliability and efficiency of their David Brown engine.