This workshop repair service manual covers the Allis Chalmers RC, WC, and WD models, representing iconic tractors known for their durability and performance in agricultural applications. These machines were built with robust engineering, designed for reliability and efficiency in demanding work environments. This manual provides comprehensive information for all engine variants, transmission types, and trim levels, ensuring that owners and technicians have access to the detailed documentation needed to maintain these classic vehicles. The purpose of this manual is to provide professional technician-level diagnostic, repair, and maintenance information for the Allis Chalmers RC, WC, and WD series. It covers a wide array of systems including the engine, lubrication, cooling, fuel, clutch, transmission, drive chain, rear axle, brakes, front axle, steering, shocks, body work, intake, exhaust, and hydraulic systems. With hundreds of pages of detailed instructions, diagrams, and illustrations, this manual facilitates routine maintenance, advanced troubleshooting, and complete disassembly and reassembly procedures, empowering users to save time and money on repairs.