This service manual provides comprehensive information for the Hitachi ZAXIS 40U-2 / 50-2 excavators, designed for robust performance in various construction and excavation tasks. These machines are engineered for reliability and efficiency, featuring a powerful diesel engine and a hydrostatic transmission for smooth operation and precise control. Their construction emphasizes durability and operational excellence, making them a valuable asset for demanding job sites. The purpose of this manual is to serve as a definitive guide for owners, technicians, and mechanics. It covers essential maintenance procedures, detailed troubleshooting steps, critical technical specifications, and vital safety guidelines necessary for the upkeep and repair of the Hitachi ZAXIS 40U-2 / 50-2. By following the instructions within this English language service manual, users can ensure optimal performance, longevity, and safe operation of their equipment.