This service and repair workshop manual covers the Allis-Chalmers Model B, Model C, Model CA, and Model G tractors, produced between 1937 and 1957. These tractors represent a significant era in agricultural mechanization, known for their robust engineering and reliability. The Model B, introduced in 1937, became a highly successful and affordable utility tractor. The Model C, launched in 1940, offered increased power, followed by the evolved Model CA in 1948 with enhanced features. The unique Model G, released in 1947, provided a distinct approach to utility tractor design. Each model, powered by various gasoline engines and equipped with manual transmissions, offered dependable performance for a wide range of agricultural tasks. This comprehensive manual provides essential repair and maintenance information for these classic Allis-Chalmers tractors. It covers all major systems, including the engine, transmission, electrical system, fuel system, hydraulic system, chassis, steering, and brakes. Detailed procedures for routine maintenance, troubleshooting, repair, overhaul, disassembly, assembly, and adjustments are included. With step-by-step instructions, diagrams, illustrations, and wiring schematics, this manual is designed to assist mechanics, independent service professionals, and owners with basic mechanical skills in maintaining and repairing their tractors, offering dealership-level technical data to ensure accurate and cost-effective service.