The Hitachi Zaxis 40U / 50U Excavator represents the 5th generation of the Zaxis series, engineered for robust performance and reliability in demanding work environments. These excavators are designed with a focus on operator comfort and operational efficiency, featuring a hydrostatic transmission for smooth, infinitely variable speed control and a variable displacement piston pump hydraulic system for precise power delivery. Their compact yet powerful build, with operating weights ranging from approximately 3,700 to 5,200 kg, makes them versatile for a variety of construction and landscaping tasks. The inclusion of features like ROPS/FOPS compliant cabs and compatibility with a range of attachments further enhances their utility and safety. This Service Repair Workshop Manual provides comprehensive guidance for the maintenance and repair of the Hitachi Zaxis 40U / 50U Excavator. It covers essential information including detailed maintenance procedures, troubleshooting diagnostics, technical specifications, and safety guidelines. The manual is intended to assist owners, mechanics, and technicians in ensuring the optimal performance, longevity, and safe operation of the equipment. By offering in-depth knowledge of the machine's systems, from the diesel engine and hydrostatic transmission to the hydraulic circuits and undercarriage, this manual serves as an indispensable resource for all aspects of equipment care.