This workshop service repair manual covers the Hitachi ZX40U-3 compact excavator, a versatile machine designed for a wide range of construction and landscaping applications. Known for its robust engineering and reliable diesel engine, the ZX40U-3 offers efficient operation with its approximately 34 HP (25 kW) water-cooled engine and hydrostatic transmission. Its compact dimensions, including an operating weight of approximately 3,800-4,000 kg and a width over tracks of about 1.75 m, make it suitable for navigating confined job sites while maintaining impressive digging and lifting capabilities. This comprehensive manual provides essential information for the maintenance, repair, and troubleshooting of the Hitachi ZX40U-3. It details critical technical specifications, engine and transmission information, fluid capacities, and recommended service intervals. Owners, technicians, and mechanics will find detailed procedures and guidance to ensure the longevity and optimal performance of their equipment, covering everything from routine servicing to more complex repairs. The manual is presented in English and serves as an indispensable resource for all aspects of ZX40U-3 operation and upkeep.