The Hitachi Zaxis 225USR-3 is a hydraulic excavator from the USR-3 Series, engineered for robust performance and reliability in demanding work environments. This model features a powerful Cummins QSB6.7 diesel engine, delivering 124 kW (166 hp) of net power, and a hydrostatic drive transmission with 4WD for optimal traction. Its design emphasizes operational efficiency, with a maximum digging depth of 6,720 mm and a maximum reach at ground level of 10,030 mm. The excavator boasts a ROPS/FOPS certified cab and pilot-operated hydraulic controls, ensuring operator safety and precise command over its 21,800 kg operating weight. This Service and Repair Manual provides comprehensive guidance for the Hitachi Zaxis 225USR-3 hydraulic excavator. It covers essential maintenance procedures, including fluid capacities and typical service intervals for engine oil and hydraulic filters, alongside detailed troubleshooting steps. Technical specifications for the engine, transmission, dimensions, and performance capabilities are thoroughly documented. This manual is an indispensable resource for owners, mechanics, and technicians seeking to maintain, repair, and optimize the performance of their Zaxis 225USR-3, ensuring its longevity and operational readiness.