This manual covers the JCB 509-42 Telescopic Handler, a robust piece of equipment designed for demanding work environments. Engineered for reliability and efficiency, this machine offers significant lift height and load capacity, making it suitable for a wide range of construction, agricultural, and industrial applications. Its construction prioritizes durability and operational performance, ensuring it meets the rigorous standards expected in its intended use. The purpose of this comprehensive Workshop Service Repair Manual is to provide detailed guidance for the maintenance, repair, and servicing of the JCB 509-42 Telescopic Handler. It includes step-by-step instructions, exploded and sectional drawings, and hundreds of photos and illustrations to facilitate understanding of all procedures. The manual covers routine maintenance, body and framework, electrics, hydraulics, transmission, brakes, steering, engine, and electronic networks, along with detailed troubleshooting sections, including electrical diagrams. Safety information, including notes, cautions, and warnings, is integrated throughout for safe operation and repair.