The Hitachi ZX50U-3 is a robust piece of equipment designed for demanding work environments. This model, part of the U-3 Series, features a powerful Isuzu 4JG1 diesel engine, delivering 40.4 kW of power, and a hydrostatic swing and travel transmission for precise control. With an operating weight of 4,990 kg and impressive digging capabilities, including a maximum digging depth of 3,730 mm and a reach of 6,030 mm, the ZX50U-3 is engineered for efficiency and reliability in various construction and excavation tasks. Its compact dimensions, with an overall width of 1,980 mm and height of 2,530 mm, allow for maneuverability in tight spaces. This Workshop Service Repair Manual provides comprehensive guidance for the Hitachi ZX50U-3. It covers essential maintenance procedures, detailed troubleshooting steps, and critical technical specifications necessary for optimal performance and longevity. Owners, mechanics, and technicians will find detailed information on engine systems, including lubrication and cooling, as well as transmission, hydraulic systems, and performance metrics. This manual is an indispensable resource for ensuring the safe and effective operation, maintenance, and repair of the ZX50U-3, written in English for clarity and ease of use.