This document provides comprehensive service information for the Hitachi ZX50U-3 Hydraulic Excavator. Engineered for reliability and performance, this excavator is designed to meet the demands of various construction and earthmoving applications. Its robust construction, coupled with efficient operation, makes it a valuable asset for professional use. Key features include a hydrostatic transmission with two-speed travel motors, a liquid-cooled diesel engine, and pilot controls for precise operation of boom, arm, and bucket functions. The excavator's operating weight is approximately 4,750 kg, with a maximum digging depth of 3.84 meters and a reach of 5.98 meters, highlighting its capability in challenging work environments. This Workshop Service Manual (WSM) offers in-depth repair and maintenance procedures for the Hitachi ZX50U-3 Hydraulic Excavator. It covers essential areas such as detailed technical specifications, routine maintenance schedules, fluid capacities, and troubleshooting guides. The manual is intended to assist owners, technicians, and mechanics in understanding the vehicle's systems, performing necessary repairs, and ensuring optimal performance and longevity. By following the outlined procedures and guidelines, users can effectively maintain the excavator's operational integrity and safety standards.