This workshop service manual covers the JCB JS235, JS240, and JS260 Auto Tier 3 tracked excavators. These robust machines are engineered for demanding construction and earthmoving applications, featuring powerful Cummins engines and efficient hydrostatic transmissions with variable displacement piston motors and planetary gearboxes. The JS235 is powered by a QSB6.7 engine producing 123 kW (165 hp) and has an operating weight of approximately 23,500 kg. The JS240 and JS260 models utilize the QSC8.3 engine, delivering 141 kW (189 hp) and 160 kW (215 hp) respectively, with operating weights of approximately 24,500 kg and 26,000 kg. All models comply with Tier 3 emissions standards. This comprehensive manual provides essential information for the maintenance and repair of your JCB excavator. It details maintenance schedules, fluid capacities for engine oil, hydraulic systems, and fuel tanks, along with technical specifications for performance and undercarriage components. Owners, technicians, and mechanics will find detailed procedures, troubleshooting guides, and diagrams to ensure optimal performance, reliability, and longevity of the equipment. The manual is presented in English and is intended to be a definitive resource for all service-related needs.