The Hitachi ZAXIS Dash-3 Series excavators, including models such as the ZAXIS 330-3, 350LCK-3, 350LC-3, and 350LCN-3, represent robust engineering designed for demanding construction and excavation tasks. These machines are powered by efficient diesel engines, commonly the Cummins QSL9, delivering approximately 250 to 270 horsepower and featuring a water-cooled system. Their construction emphasizes reliability and performance, with hydrostatic swing and travel drives, automatic speed control, and substantial operating weights typically ranging from 30,000 to 35,000 kg. Notable capabilities include impressive digging depths of up to 7,000 mm and a reach at ground level of around 10,500 mm, supported by powerful hydraulic systems utilizing variable displacement piston pumps. This Service Repair Manual provides comprehensive guidance for the Hitachi ZAXIS Dash-3 Series excavators. It covers essential maintenance procedures, detailed troubleshooting steps, critical technical specifications, and vital safety guidelines necessary for the upkeep and repair of these heavy-duty machines. The manual is intended to assist owners, mechanics, and technicians in understanding the intricate systems of the excavator, ensuring optimal performance, longevity, and operational safety. It details engine specifications, hydraulic system parameters, undercarriage components, and fluid capacities for various maintenance intervals.