The Hitachi Zaxis 225US is a robust excavator designed for demanding construction and industrial applications. Engineered for reliability and efficiency, this machine features a powerful Hino J07E-TK diesel engine delivering 120 kW (161 hp) and a hydrostatic transmission with variable speed control. Its substantial operating weight of 23,700 kg (52,250 lbs) and impressive dimensions, including a length of 9,950 mm (32 ft 8 in) with the bucket and a width over tracks of 2,990 mm (9 ft 10 in), underscore its capability in various work environments. The ROPS/FOPS certified cab ensures operator safety and comfort during extended use. This Workshop Service Manual provides comprehensive guidance for the repair and maintenance of the Hitachi Zaxis 225US. It covers essential procedures, technical specifications, and troubleshooting information to ensure optimal performance and longevity of the equipment. Key areas detailed include engine specifications, hydraulic system parameters, undercarriage maintenance, and fluid capacities, such as the 20.5-liter engine oil capacity and 300-liter hydraulic system oil capacity. Regular adherence to the maintenance schedules, like the 500-hour engine oil change interval, is crucial for sustained operational efficiency.