This manual covers the JCB JS115, JS130, and JS145 Auto Tier3 tracked excavators, designed for robust performance in various construction and earthmoving applications. These excavators are engineered with powerful Cummins QSB4.5 diesel engines, offering reliable operation and efficiency. Notable features include ROPS and FOPS compliant safety cabs, variable displacement travel motors for precise maneuverability, and options for monoboom or two-piece booms with a range of bucket capacities. The robust construction and advanced hydraulic systems ensure durability and productivity across demanding work environments. The purpose of this workshop repair service manual is to provide comprehensive technical information for the maintenance, repair, and servicing of your JCB tracked excavator. It details essential procedures, specifications, and troubleshooting guidance covering engine, transmission, hydraulic systems, undercarriage, and cab components. This manual is an indispensable resource for owners, operators, and service technicians, enabling them to perform routine maintenance, diagnose issues, and execute repairs accurately, ensuring the longevity and optimal performance of the equipment.