This manual covers the International Harvester 986 Tractor, a robust diesel machine produced approximately between 1976 and 1981. As part of the esteemed IH '86' series, the 986 represented an evolution in row-crop tractor design, offering updated features and styling. Known for its reliable inline 6-cylinder diesel engine, estimated to produce between 90-100 PTO horsepower, this tractor was engineered for demanding agricultural tasks. Its substantial operating weight and powerful torque made it a capable workhorse for various farm operations. The International Harvester 986 Tractor is recognized for its solid construction and enduring performance, making it a valuable asset for owner-operators and agricultural professionals. This comprehensive service repair manual provides detailed information for the maintenance, repair, and troubleshooting of the International Harvester 986 Tractor. It covers all major systems, including the engine, transmission, brake system, electrical system, cooling system, and fuel injection. The manual includes procedures for general maintenance, disassembly and reassembly, periodic lubrication, and in-depth diagnostics. Its purpose is to empower owner-operators, farm technicians, and repair shops with the knowledge needed to perform independent repairs, saving costs and ensuring the longevity of the tractor. This resource is essential for anyone seeking to maintain or repair this iconic piece of agricultural machinery.