The Komatsu PC78MR-6 Hydraulic Excavator, part of the MR-6 Series, is engineered for demanding work environments. This robust machine features a Komatsu SAA4D102E-2 diesel engine, delivering a net power of 58.7 kW (78.7 HP). Its hydrostatic 4-wheel drive system ensures efficient power transfer, while its compact dimensions, including an operating weight between 7,770 and 8,070 kg, make it versatile for various job sites. The PC78MR-6 is designed for reliability and performance in construction and earthmoving applications. This Workshop Service Manual provides comprehensive guidance for the repair and maintenance of the Komatsu PC78MR-6 Hydraulic Excavator. It covers essential technical specifications, detailed maintenance procedures, and troubleshooting information to assist owners, mechanics, and technicians. The manual aims to ensure the longevity and optimal performance of the equipment by offering clear instructions and diagrams for all service-related tasks.