This manual covers the Komatsu PC25-1 hydraulic excavator and its variants, including the PC30-7, PC40-7, and PC45-1. These machines are engineered for robust performance and reliability in various construction and earthmoving applications. Featuring efficient diesel engines and hydrostatic transmissions with hydraulic motor drive, they offer precise control and dependable operation. The models vary in operating weight, dimensions, and engine power, providing a range of capabilities to suit different project demands. This Workshop Service Manual provides comprehensive repair and service information for the specified Komatsu hydraulic excavators. It details essential maintenance procedures, including lubrication schedules and filter replacement intervals, along with technical specifications for engines, transmissions, and dimensions. The manual is designed to assist owners, mechanics, and technicians in performing routine maintenance, troubleshooting issues, and executing repairs, ensuring the continued optimal performance and longevity of the equipment.