Part of the Hitachi Repair Manuals.
Need the factory answer for your Hitachi EX120 hydraulic excavator? All 984 pages of this Hitachi EX120 service manual PDF dig into the real machine: hydraulic pump device, control valve, swing device, travel device, undercarriage, and a full engine section. You get complete wiring diagrams, hydraulic schematics with full circuit routing, exploded views for every major assembly, and a heavy troubleshooting section built for chasing real faults. Set pilot valve primary pressure at 40 kgf/cm2 (3900 kPa) and confirm the solenoid relief valve cracks above 38 kgf/cm2 (3700 kPa) before you blame the pump. No more diagnosing a dead swing circuit with a gauge and a guess. Bookmarked with a live text layer; pull it up on your tablet, search the spec, and get wrenching.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| How to Use | 1-11 | Section & Group Contents, Introduction, This Manual, Safety Informations |
| Specifications | 12-41 | General Specifications, Components Specifications, Torque References, Others, Conversion Table |
| General | 42-85 | Introduction, Hydraulic System, Electric System, Maintenance |
| Superstructure | 86-391 | Hydraulic Pump Device, Control Valve, Swing Device, Pilot Valve, Mode Selection Cylinder |
| Undercarriage | 392-541 | Travel Device, Center Joint |
| Front-End Attachment | 542-589 | Hydraulic Cylinder, Pin & Bushing, Point & Side Cutter |
| Hydraulic System | 590-641 | Main Hydraulic Circuit, Pilot Circuit, Single Operation, Combined Operation, Extra Control Circuit, Hydraulic Circuit |
| Electrical System | 642-703 | Safety Precautions, Specifications, Construction & Function, Circuit Operations, Maintenance |
| Troubleshooting | 704-812 | Introduction, Diagnose Malfunctions, Excavator Performance Test, Components Performance Standard, Electrical System Test |
| Engine | 813-984 | General Information, Maintenance, Engine Disassembly, Inspection & Repair, Engine Assembly, Lubricating System, Cooling System, Fuel System, Turbo Charger, Engine Electricals, Troubleshooting, Special Tool List |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Engine weight (4BD1T) | 340 kg | p. 822 |
| Engine oil capacity | 13 L | p. 822 |
| Coolant capacity (Engine only) | 8.5 L | p. 822 |
| Valve clearance (Inlet/Exhaust) | 0.4 mm | p. 20 |
| Injection pressure | 185 kgf/cm2 | p. 20 |
| Pilot pump rated pressure | 40 kgf/cm2 | p. 23 |
| Swing motor output torque | 389 N.m | p. 24 |
| Travel reduction device lubrication oil capacity | 3.5 L | p. 410 |
| Track link tightening torque | 45 kgf.m | p. 454 |
| Battery capacity | 65AH x 2 | p. 19 |
