Part of the Hitachi Operator Manuals.
Low gear oil in a swing reduction unit or a missed greasing interval on the front pins shows up as wear you pay for in hours, and the Hitachi EX120 operator manual PDF (OEM ID EM12H-1-4) is the 138-page book that keeps those checks on schedule for this hydraulic excavator. The maintenance guide takes up about a quarter of the book and covers greasing, engine oil, gear oil, hydraulic, fuel, air intake, cooling and electrical service by interval. Hydraulic and electrical circuit layouts show where each component sits on the machine. Troubleshooting charts sort engine, control and hydraulic complaints by cause and remedy. Fill each propel reduction unit with 3.5 L of gear oil and the swing reduction unit with 3.2 L, then tighten the pilot filter element to 20-29 N·m. Guessing a final drive fill level can cost you a whole shift. Bookmarks and a searchable text layer take you straight to the interval chart you need.
What's Inside This Operator Manual
| System | Pages | Key Topics |
|---|---|---|
| Operation Manual | 1-2 | Warranty, Machine Numbers, Directions, Safety, Measurements |
| To the Operator | 7-10 | Understand Machine Operation, Wear Protective Clothing, Precautions for Inspection |
| Name and Function of Components | 11-34 | Controls, Instrument Panel, Accelerator Lever, Starter Switch, Gauges and Indicators, Mode Selection, Auto Idling Device, Propel Levers |
| Inspect Excavator Daily Before Starting | 35-36 | Front Attachment, Arm Cylinder, Bucket Cylinder |
| Operation | 37-40 | Starting the Engine, Starting Procedure for Cold Conditions, Checking Instrument After Starting, Stopping the Engine, Warming-Up, Warming Excavator During Cold Weather |
| Basic Machine Operation | 41-50 | Move Excavator Safely, Carry Bucket Low, Avoid Tipping, Operate with Caution, Avoid Power Lines, Check Work Site, Operating in Water or Mud, Avoid Hard Digging |
| Transporting | 51-54 | Loading the Excavator, Center the Excavator on the Trailer, Dimensions for Transportation, Transportation of Long Arm Front Attachment |
| To the Mechanic | 55-56 | Warranty, Measurements |
| Safety Precautions for Mechanics | 57-60 | Understand Correct Service, Stop the Engine, Precautions for Inspection and Maintenance, Service Hydraulic System Safely, Lock the Engine Hood, Support Raised Equipment |
| Components Locations and Circuits | 61-70 | General, Hydraulic System, Electrical Circuit |
| Maintenance | 71-105 | Maintenance Guide |
| Maintenance Services Under Various Conditions | 106-108 | Storing the Excavator |
| Assembly of Front-End Attachment | 109-118 | Open Package, Check Items and Quantity, Prepare Equipment and Materials, Clean Connecting Portions, Remove Blind Plug, Mount the Boom, Connect Rod-End Side Boom Cylinder |
| Troubleshooting | 119-126 | Engine, Electrical System, Heater, Control System, Hydraulic System |
| Specifications | 127-132 | Operating Weight, Engine, Working Ranges, Shoe Types, Bucket Types |
| Handling Optional Attachments | 133-138 | Hydraulic Breaker, Hydraulic Oil Replacement, Filter Element, Pressure Release, Crusher |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Swing reduction unit gear oil capacity | 3.2 L | p. 80 |
| Propel reduction unit gear oil capacity | 3.5 L x 2 | p. 74 |
| Pilot filter element tightening torque | 20-29 N·m (2-3 kgf·m) | p. 80 |
| Low pressure hydraulic hose clamp torque | 5.9-6.9 N·m (0.6-0.7 kgf·m) | p. 87 |
| Propel reduction device plug fastening torque | 49 N·m (5 kgf·m) | p. 74 |
| Union joints of hydraulic hoses and pipings (19mm) | 29 N·m (3 kgf·m) | p. 103 |
| Union joints of hydraulic hoses and pipings (22mm) | 39 N·m (4 kgf·m) | p. 103 |
| Engine Oil Replacement Capacity | 15L | p. 78 |
| Propel Reduction Device Oil Capacity | 3.5L x 2 | p. 80 |
| Fuel Tank Capacity | 250L | p. 89 |
| Propel Reduction Device Oil Drain Plug Torque | 49 N·m | p. 80 |
| Full Flow Filter Element Bolt Fastening Torque | 49 N·m | p. 85 |
