This manual covers the Allis-Chalmers B Series Tractors, including models such as the B-1, B-10, B-12, B-110, B-112, HB-112, HB-212, B-206, B-206E, B-207, B-207E, B-208, B-208E, and Big Ten. These tractors, produced from the late 1930s through the 1950s and into the early 1960s, are known for their robust engineering and historical significance in American agriculture. Allis-Chalmers was a prominent manufacturer, and the B Series models were foundational, offering versatility and affordability. This comprehensive repair manual provides essential technical information for maintaining and repairing these durable vintage tractors. The purpose of this manual is to offer detailed guidance on the repair, maintenance, and troubleshooting of your Allis-Chalmers B Series tractor. It covers key systems including the engine, drivetrain, chassis, and electrical systems, with specific procedures for routine maintenance, engine rebuilds, transmission servicing, and electrical system diagnosis. Advanced troubleshooting guides are included to address common operational issues. This resource is designed for owners, operators, and mechanics, providing the necessary technical specifications and procedures to ensure the longevity and optimal performance of these iconic agricultural machines.