Hitachi EX120-5 Excavator Repair Manual

Hitachi EX120-5 Technical Service Documentation

• Covers the Hitachi EX120-5 excavator with focus on upperstructure components, pump device disassembly, and main frame removal
• Original OEM publication, copyright Hitachi Construction Machinery Co. Ltd.
• Contains 56 detailed exploded-view diagrams of the hydraulic pump and structural assemblies
• Features 12 comprehensive torque specification tables for critical structural bolts and hydraulic fittings
• Laid out for standard letter and A4 printing
• Accessible from your device as soon as the order is placed
• This specific edition provides the precise clearance limits for hydraulic pump internal components necessary for precision reassembly of the EX120-5 main pump device

Component and Assembly Overview

The 2006 Hitachi EX120-5 service documentation details the structural and hydraulic systems required for maintenance and repair of the upperstructure. The publication outlines procedures for the removal and installation of the cab, counterweight, and main frame, while providing specific weight capacities and lifting requirements for each major component to aid safe handling in a workshop environment.

Technical chapters document the assembly and disassembly of the hydraulic pump device, including regulator components, pilot pumps, and selector heads. These sections include critical information on aligning marks, floating seal precautions, and bleeding air from hydraulic circuits to ensure proper system performance after service. The documentation highlights maintenance standards for gear backlash and critical clearances between internal pump components like plungers, cylinder blocks, and servo pistons, providing clear standard and allowable limits.

Specifications and Torque Reference

Torque charts are provided for various bolt types, including hexagon T, H, and M bolts, along with guidance on lubricant applications for thread stabilization. Specific fastener torque values are listed for essential components, such as the 390 Nm (290 lbf.ft) requirement for swing bearing-to-upperstructure bolts and 1130 Nm (830 lbf.ft) for the counterweight. Piping joint specifications are defined by union nut size, with values for 30° and 37° joints ensuring leak-free connections. For more detailed insights into how factory workshop documentation is structured, users can reference our technical guide. All service data shown here is for reference only — qualified technicians and the original OEM documentation remain the authoritative source for any hands-on work. This official Hitachi publication provides the technical data, torque values, and assembly procedures necessary for maintaining the 2006 Hitachi EX120-5 excavator, covering major upperstructure systems and hydraulic pump maintenance standards.