The Komatsu PC138US-8 is a robust and reliable excavator designed for a wide range of construction and earthmoving applications. Engineered with precision, this model, part of the US-8 Series, features a powerful SAA4D95LE-5 engine delivering 71.1 kW of power, coupled with a hydrostatic transmission for efficient operation. Its compact design, with an operating weight of 13900 kg and dimensions optimized for maneuverability, makes it suitable for confined job sites. The PC138US-8 is built to deliver exceptional performance, offering a maximum digging depth of 5825 mm and a standard bucket capacity of 0.54 m³, embodying Komatsu's commitment to quality and productivity. This comprehensive Operation and Maintenance and Shop Manual provides essential information for the Komatsu PC138US-8. It covers critical aspects including detailed maintenance procedures, fluid capacities, service intervals for engine oil and hydraulic filters, and troubleshooting guidance. Technical specifications, such as engine details, transmission type, and undercarriage measurements, are thoroughly documented. Safety guidelines are also included to ensure safe operation and maintenance practices. This manual serves as an indispensable resource for owners, operators, and technicians seeking to maintain the optimal performance and longevity of their PC138US-8 excavator.