This document is the service manual for Farmall tractors models 110A, 120A, 125A, and 140A. It contains sections on the engine, transmission, four-wheel drive system, front and rear axle systems, power take-off, brakes and controls, hydraulic systems, hitches and drawbars, steering, cab climate control, electrical systems, platform and decals. The introduction emphasizes the importance of protecting the environment and following safety procedures when operating farm equipment.