This service and repair workshop manual provides comprehensive instructions for the David Brown AD4 25 engine. Designed for mechanics worldwide, this manual covers all major topics necessary for the upkeep and restoration of this engine. The David Brown AD4 25 engine is recognized for its robust engineering and reliable performance, making it a dependable choice for its intended applications. The scope of this manual is extensive, detailing essential maintenance procedures, diagnostic troubleshooting steps, and technical specifications crucial for effective repair. It serves as an indispensable resource for owners, mechanics, and technicians, enabling them to maintain the David Brown AD4 25 engine in optimal working condition and address any issues that may arise. Adherence to the guidelines within this manual ensures the longevity and efficiency of the vehicle.