The 90 Series Tractors, produced from the mid-1980s through the 1990s, represent a robust and reliable line of agricultural machinery. This series, encompassing models such as the 115-90, 130-90, 140-90, 160-90, and 180-90, was developed from earlier tractor designs, incorporating significant advancements in power, operator comfort, and technology for its time. Known for their durability and strong performance, these tractors are powered by 8000 Series Engines, which vary in displacement from 6.1 to 10.0 liters and are available in naturally aspirated and turbocharged diesel configurations. Transmission options include Synchromesh 12-speed or 20-speed powershift systems, offering on-the-go shifting for enhanced productivity. The 90 Series is widely recognized for its ruggedness and ease of repair, making it a dependable choice for farmers and agricultural professionals. This comprehensive Workshop Manual, presented in English, is designed to assist owners, agricultural technicians, and mechanics in maintaining and repairing their 90 Series tractors. Spanning 507 pages, it covers a vast array of systems and procedures, including detailed engine overhaul instructions, transmission servicing for both mechanical and powershift types, and in-depth guidance on the hydraulic lift system. The manual also provides thorough coverage of the electrical system, front axle and steering, braking system, cooling system, fuel system, power take-off (PTO) systems, and operator cab components. Furthermore, it includes essential information on routine maintenance, troubleshooting guides, major component rebuilds, tightening torque specifications, calibration procedures, and the identification of special tools required for various repair tasks, ensuring that these tractors can be kept operational with minimal downtime.