This workshop service repair manual covers the Hitachi ZX40U-3 compact excavator, a robust machine designed for a variety of construction and landscaping tasks. Part of the U-3 Series, this model features a powerful Isuzu diesel engine with a displacement of 2.17 L, delivering approximately 38.7 HP. Its hydrostatic swing and travel system, coupled with an operating weight of around 3,900 kg, makes it a versatile and reliable tool for demanding job sites. The ZX40U-3 is engineered for efficiency and durability, offering impressive digging depth and reach for its class. This comprehensive manual provides essential information for the maintenance, repair, and troubleshooting of the Hitachi ZX40U-3. It details critical technical specifications, including engine and hydraulic fluid capacities, along with recommended maintenance intervals for engine oil and hydraulic filters. The manual also outlines operating characteristics such as travel speed, digging performance, and ground pressure. This resource is intended to assist owners, technicians, and mechanics in ensuring the optimal performance and longevity of their ZX40U-3 excavator through accurate and detailed guidance.