The Hitachi Zaxis 225US / 225USR is a versatile excavator designed for demanding construction and earthmoving applications. Built with robust engineering, this machine features a powerful Cummins QSB6.7 diesel engine, delivering approximately 170 HP, and a hydrostatic transmission for efficient power delivery. Its substantial operating weight of around 21,700 kg, combined with a track gauge of 2,200 mm and 440 mm ground clearance, provides stability and maneuverability on various job sites. The excavator offers impressive performance capabilities, including a maximum digging depth of 6,600 mm and a maximum reach of 9,870 mm with its standard boom, and a bucket capacity ranging from 0.8 to 1.1 m³. This Service Repair Manual provides comprehensive guidance for the maintenance, repair, and technical understanding of the Hitachi Zaxis 225US / 225USR excavators. It covers essential areas such as detailed repair procedures, routine maintenance schedules, troubleshooting common issues, and in-depth technical specifications. The manual includes diagrams and information on critical systems like the engine, transmission, and hydraulics, along with fluid capacities for engine oil, hydraulic oil, and coolant. This resource is invaluable for owners, mechanics, and technicians seeking to ensure the optimal performance, longevity, and safe operation of their equipment.