The Komatsu PC128UU-1 and PC128US-1 excavators represent robust engineering designed for demanding work environments. These machines, part of the UU/US Series, are powered by Komatsu 102 Series Diesel engines, available in 4.989 L (4-cylinder) and 7.13 L (6-cylinder) configurations, delivering up to approximately 78.4 kW (105 HP). Featuring a hydrostatic transmission with variable speed control and a standard bucket capacity of approximately 0.52 m³, these excavators are built for reliability and efficiency in a wide range of construction and earthmoving applications. Their operating weight ranges from approximately 12,800 to 13,700 kg, with impressive digging depths of up to 4.87 m and a maximum reach of 7.79 m, showcasing their powerful performance capabilities. This comprehensive Shop Manual and Engine Manual, provided in English, serves as an essential resource for maintaining and repairing the Komatsu PC128UU-1 and PC128US-1 excavators. It details critical maintenance procedures, including recommended service intervals for engine oil and hydraulic filter changes, along with lubrication capacities for engine and hydraulic systems. The manual also covers technical specifications, troubleshooting guidance, and safety protocols. By offering in-depth information on the hydrostatic drivetrain, hydraulic system, and engine details, this guide empowers owners, mechanics, and technicians to ensure optimal performance, longevity, and operational safety of their equipment.