The Hitachi Zaxis 225USR-3 is a robust excavator designed for demanding construction and earthmoving applications. Featuring a powerful 6.98 L diesel engine producing 121 kW (162 hp) with direct injection and meeting EPA Tier 3 / EU Stage IIIA emissions standards, this machine is engineered for efficiency and reliability. Its hydrostatic transmission with variable speed and hydraulic pilot control ensures precise operation, while its substantial operating weight of 22,400 kg and impressive digging capabilities, including a maximum depth of 6,710 mm and reach of 9,870 mm, make it a versatile tool for various project requirements. This Workshop Service Repair Manual provides comprehensive guidance for the maintenance and repair of the Hitachi Zaxis 225USR-3. It covers essential technical specifications, detailed maintenance procedures for key fluid capacities and lubrication points, and information on its undercarriage and performance metrics. The manual is intended to assist owners, technicians, and mechanics in understanding the machine's systems, performing routine servicing, and troubleshooting potential issues, thereby ensuring optimal performance and longevity of the equipment.