Hitachi EX120-5 Excavator Repair Manual (OEM)

• Covers the Hitachi EX120-5 excavator with a focus on upperstructure components, pump device disassembly, and main frame removal
• Original OEM publication by Hitachi Construction Machinery Co. Ltd.
• Contains 56 detailed exploded-view diagrams of the hydraulic pump and structural assemblies
• Features 12 torque specification tables for critical structural bolts and hydraulic fittings
• Provides the precise clearance limits for hydraulic pump internal components necessary for accurate reassembly

Component and Assembly Overview

This 2006 Hitachi EX120-5 service material breaks down the structural and hydraulic systems required to maintain the upperstructure. It outlines the removal and installation of the cab, counterweight, and main frame. You get specific weight capacities and lifting requirements for every major component. That means safer handling in the bay.

Technical chapters dive into tearing down and building up the hydraulic pump device. This covers regulator components, pilot pumps, and selector heads. You will find critical details on aligning marks, handling floating seals, and bleeding air from hydraulic circuits so the system runs right after a rebuild. The documentation lays out clear maintenance standards for gear backlash. It also provides the standard and allowable limits for internal pump parts like plungers, cylinder blocks, and servo pistons.

Specifications and Torque Reference

Torque charts cover hexagon T, H, and M bolts. The text includes guidance on lubricant applications for thread stabilization. Fastener torque values are strictly defined for essential parts. For example, the swing bearing-to-upperstructure bolts require 390 Nm (290 lbf.ft), while the counterweight needs 1130 Nm (830 lbf.ft). Piping joint specs are categorized by union nut size, detailing values for 30° and 37° joints to ensure leak-free connections.

Working on heavy excavators involves massive weights and high-pressure hydraulics. Always verify your lift capacities and pressure release protocols before starting a job to prevent equipment damage or personal injury. Relying on this official factory data ensures you hit the exact torque values and assembly standards for the EX120-5 without second-guessing.