The Hitachi Zaxis 225US-3 Hydraulic Excavator represents a significant advancement in compact construction equipment, engineered for precision operation and robust performance in various demanding environments. This model, part of the US-3 Series, is built upon a foundation of reliability and efficiency, featuring a powerful ISUZU AH-6HK1X 7.8 L diesel engine that delivers 123 kW (165 hp) of gross power. Its design emphasizes operator comfort and productivity, incorporating a hydrostatic, variable speed drive system with two-speed travel motors for optimal maneuverability. With an operating weight of approximately 21,400 kg, the Zaxis 225US-3 is a versatile machine suited for a wide range of earthmoving and construction applications. This Full Service Repair Manual provides comprehensive guidance for the maintenance, repair, and troubleshooting of the Hitachi Zaxis 225US-3 Hydraulic Excavator. It covers essential information, including detailed procedures for servicing the engine, hydraulic system, and drive components, alongside specifications for lubricants and capacities. The manual is designed to assist owners, technicians, and mechanics in understanding the machine's systems, performing routine maintenance, and addressing any operational issues. By following the instructions and adhering to the technical specifications outlined within, users can ensure the longevity, optimal performance, and safe operation of their equipment.