This manual covers the Allis Chalmers HB-112 Tractor, a model from a historic American manufacturer renowned for agricultural and construction equipment. The HB-112 is part of the HB series and represents a specific offering within Allis Chalmers' tractor line. While specific production years are not detailed, this service repair workshop manual provides comprehensive information for this model. The Allis Chalmers brand is associated with engineering quality and reliability, and this manual aims to preserve that legacy by offering detailed technical guidance. The purpose of this English-language manual is to provide full service and repair instructions for the Allis Chalmers HB-112 Tractor, comparable to dealership technician resources. It covers all major topics, including routine and scheduled maintenance, engine service, hydrostatic drive unit and powertrain repair, and electrical system diagnostics with wiring schematics. The manual also includes specific coverage for B-Series Attachments and general troubleshooting guidance with diagrams and illustrations. It is designed for owners with basic mechanical skills and independent service professionals, enabling them to perform maintenance and repairs effectively and cost-efficiently.