The Hitachi ZX135USL-3 is a robust crawler excavator engineered for demanding construction and excavation tasks. This model, powered by an Isuzu 4HK1X diesel engine, offers a net power of 66.4 kW (89 hp) and features a hydrostatic transmission with two-speed travel motors for efficient operation. Its compact design, with a width over tracks of 2.59 meters, makes it suitable for various job sites, while its operating weight ranges from 13600 to 14700 kg. The ZX135USL-3 is built for reliability and performance, delivering impressive digging depth and reach capabilities. This Service Repair Manual provides comprehensive guidance for the Hitachi ZX135USL-3 crawler excavator. It covers essential maintenance procedures, detailed troubleshooting steps, and critical technical specifications required for effective upkeep and repair. The manual is designed to assist owners, mechanics, and technicians in ensuring the optimal performance, longevity, and safety of the equipment. All information is presented in English to facilitate understanding and application across a wide range of users.