Part of the Hitachi Repair Manuals.
Need the exact tear-down protocols for your Hitachi mini excavator? This 868-page Hitachi EX12–EX45 Series Technical Manual, Workshop Manual PDF (OEM #T587E-01) breaks down the complete undercarriage, hydraulic, and engine systems for the EX12-2, EX15-2, EX18-2, EX22-2, and EX25-2 variants. You get complete hydraulic schematics tracing the pilot circuits, full wiring diagrams for the monitor relays, and a massive troubleshooting section covering every actuator and swing system fault. Open up to step-by-step disassembly procedures for the control valves, center joints, and track adjusters to rebuild your machine right the first time. Lock down the main pump mounting bolts to exactly 49 Nm and verify your swing speed hits 8.5 rpm before sending it back to the dirt. A dead machine on the job site burns cash fast. Download this searchable, bookmarked file directly to your tablet and get your excavator moving again.
What's Inside This Hitachi EX12-2 to EX45-2 Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 2-3 | - |
| General | 4-23 | Specifications, Working Range•Transportation, Engine Specification, Main Components, Electrical System (Overall System), Electrical System (Relays) |
| System | 24-39 | Outline, Main Circuit, Pilot Circuit |
| Component Operation | 40-101 | Pump Device, Swing Device, Control Valve, Pilot Valve, Travel Device |
| Operational Performance Test | 102-153 | Engine Speed, Engine Compression Pressure, Travel Speed, Swing Speed, Main Relief Valve Set Pressure, Travel Motor Drainage |
| Troubleshooting | 154-197 | Troubleshooting a Procedure, Engine System Troubleshooting, Actuator Operating System Troubleshooting, Front Attachment System Troubleshooting, Swing System Troubleshooting |
| Attached Diagram List | 198-203 | - |
| Safety | 206-231 | - |
| General Information | 232-247 | Precautions for Disassembling and Assembling, Tightening Torque Specifications, Torque Chart, Piping Joint |
| Upperstructure | 248-347 | Pump Device, Control Valve, Swing Device, Pilot Valve, Solenoid Valve |
| Undercarriage | 348-435 | Swing Bearing, Travel Device, Center Joint, Track Adjuster, Front Idler, Upper and Lower Rollers |
| Front Attachment | 436-481 | Maintenance Standards, Remove and Install Cylinders, Disassemble and Assemble Cylinders |
| EX12-2 to EX35-2 Engine | 482-668 | Engine Body, Lubricating System, Cooling System, Intake/Exhaust System, Fuel System, Electrical System |
| EX40-2 / EX45-2 Engine | 669-868 | Engine Body, Lubricating System, Cooling System, Intake/Exhaust System, Fuel System, Electrical System |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| EX12-2 | ||
| Swing Speed | 8.5 min⁻¹ (rpm) | p. 6 |
| All Models | ||
| Hydraulic system failure with loss of digging force and slow cycle times | All machine functions are slow. | p. 165 |
| Air cleaner | M-19 | p. 148 |
| INJECTION NOZZLE | M-25 | p. 150 |
| INJECTEURS | M-26 | p. 8 |
| Piston rod tightening torque | 36 mm, 41 mm, 46 mm, 55 mm | p. 477 |
| Set screw tightening torque | 3 mm, 4 mm | p. 186 |
| EX12-2, EX15-2, EX18-2 | ||
| Main Pump mounting bolt torque | 49 Nm (5 kgf·m, 36 lbf·ft) | p. 236 |
| Pilot Pump mounting bolt torque | 25 Nm (2.5 kgf·m, 18 lbf·ft) | p. 2 |
| EX22-2, EX25-2, EX30-2, EX35-2, EX40-2, EX45-2 | ||
| Clearance between cylinder block bore and plunger (D-d) | 0.05 mm or less | p. 268 |
| Clearance between plunger tip and shoe bottom (Delta) | 0.2 mm or less | p. 268 |
Hitachi EX12-2 to EX45-2 Common Problems This Manual Covers
Hitachi EX15-2 hydraulic pump grinding noise with weak digging force and slow cycle times
Check the actuator troubleshooting chart on page 165 for all machine functions running slow. Verify main relief valve set pressure reads 195±10 kgf/cm² (page 152) for the EX15-2; adjust or replace the valve if it won't hold. Inspect main pump mounting bolts, torque to 49 Nm (36 lbf·ft) per page 236, and check for internal pump wear if pressure still won't build.
Manual Section: Actuator Operating System Troubleshooting p. 165Engine overheats and shuts down repeatedly after running under load for an hour
Clean the radiator net and fins if clogged with dust per page 166; restricted airflow is the top cause of overheating in dusty jobsites. Test thermostat opening temperature, spec is 69.5 to 72.5°C (page 552), and replace it if it sticks closed. Check the radiator cap seal, replace per page 737 if it won't hold pressure, then top off coolant to the correct level.
Manual Section: Engine System Troubleshooting p. 166Joystick controls feel dead or unresponsive with erratic front attachment movement
Check the actuator operating system troubleshooting chart on page 165 for slow or erratic function response. Measure primary pilot pressure at the pilot valve outlet, spec is 40±10 kgf/cm² (page 152); low readings point to a worn pilot pump or blocked filter screen. Inspect pilot lines for kinks or leaks and bleed air from the circuit before retesting lever response.
Manual Section: Actuator Operating System Troubleshooting p. 165Hydraulic cylinder rod seals leak oil after two to three years of operation
Remove the cylinder and inspect the rod surface for scoring or wear where the seal rides. Fit new seals and torque the piston rod nut with the correct wrench size, 36, 41, 46, or 55 mm per page 477. Reinstall on the machine and slowly cycle the cylinder to full extend and retract eight times or more (page 478) to bleed air and seat the seals before checking for weeping.
Manual Section: Front Attachment p. 477Engine cranks but won't start on cold mornings, especially below freezing
Check the engine troubleshooting chart on page 161 for starter rotates but engine does not start conditions. Verify battery voltage and cable connections first, then test fuel injection pressure at the nozzle, spec is 140 to 150 kgf/cm² (page 553); low pressure or worn injectors won't atomize fuel properly in cold air. Bleed any air from the fuel system before retrying the start.
Manual Section: Engine System Troubleshooting p. 161Black smoke pours from the exhaust along with noticeably higher engine oil consumption
Remove and inspect the air filter element; clean or replace it per page 539, since restricted intake air causes incomplete combustion and black smoke. Check engine oil level for over-fill or fuel contamination. Test fuel injection pressure against the 140 to 150 kgf/cm² spec on page 553; injectors outside that range won't atomize fuel cleanly and will also burn oil past worn rings.
Manual Section: Engine Ex12-2 to Ex35-2 p. 539Frequently Asked Questions
How can I find reset procedures, or the production years (YYYY-YYYY) for the machine?
The manual does not provide 'production years' in YYYY-YYYY format, but it lists serial number ranges for different models and types in the 'INTRODUCTION' section on pages 2-3. For reset procedures, the manual typically refers to 'adjustment' or 'setting' procedures. For example, the control lever and pedal stroke can be adjusted by loosening stopper bolts, moving the spool to its stroke end, and then tightening the bolts, as detailed on page 127. p. 127
What are the replacement specifications for the main hydraulic pump?
For installing the main hydraulic pump, the mounting bolts should be tightened to 88 N·m (9 kgf·m, 65 lbf·ft). Additionally, for maintenance, the clearance between the cylinder block bore and plunger must be 0.05 mm or less, and the shaft oil seal mount surface should be free from scratches or abnormal wear, with a wear amount of 0.025 mm or less.
What are the replacement specifications for control valve seals and O-rings?
When assembling the control valve, O-rings for the joint pins should be installed with a tightening torque of 29 N·m (3 kgf·m, 22 lbf·ft). It is important to ensure that O-rings are new, free from damage, and properly seated to prevent leaks, as detailed in the general information for O-ring seal joints. p. 288
What are the standard maximum and minimum engine speeds for the EX12-2 model?
For the EX12-2 model, the standard maximum engine speed is 2150±50 min⁻¹ and the minimum speed is 1070±70 min⁻¹. These values are used to evaluate engine performance and should be checked before performing other tests. p. 148
How quickly can I access this Hitachi EX12–EX45 Series manual after buying?
You get a 868-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Am I able to print pages from this Hitachi EX12–EX45 Series manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Are electrical wiring diagrams included in this Hitachi EX12–EX45 Series manual?
Yes. You'll find full electrical schematics with wire routing diagrams, connector identification, and circuit descriptions.
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