This manual covers the Komatsu MRX Series compact excavators, including the PC27MRX-1, PC30MRX-1, PC35MRX-1, and PC40MRX-1 models. These machines are engineered for versatility and efficiency in various construction and landscaping applications, featuring robust diesel engines and hydrostatic transmissions for precise control. Their compact design allows for operation in confined spaces, while their build quality ensures reliability and durability in demanding work environments. The purpose of this comprehensive shop and operation & maintenance manual is to provide essential information for the upkeep and repair of your Komatsu MRX Series excavator. It details maintenance procedures, troubleshooting guides, disassembly and assembly instructions, electrical and hydraulic system overviews, and technical specifications. This resource is designed to assist owners, operators, and service technicians in maintaining optimal performance and longevity of the equipment.