Part of the Hitachi Repair Manuals.
All 762 pages of this Hitachi EX80u service manual PDF focus on one machine: the EX80u hydraulic excavator, from pilot valve to final drive. You get full electrical wiring diagrams, complete hydraulic circuit schematics, and a troubleshooting section that walks electrical system inspection step by step. Workshop chapters take you through pump device, control valve, swing and travel device removal, every boom, arm, bucket, and blade cylinder, plus a full engine section covering fuel, cooling, and lubricating systems. Run the operational performance tests with real factory numbers: set main relief at 26.0 MPa for front and swing, 31.4 MPa for travel, and confirm the main pump flows 60 L/min at 2.0 MPa. No more chasing hydraulic faults with a gauge and a guess. Bookmarked and keyword-searchable; jump straight to the spec and get back under the boom.
What's Inside This Hitachi EX80u Manual
| System | Pages | Key Topics |
|---|---|---|
| Service Manual | 1 | Operational Principle, Troubleshooting, Circuit Diagram, Harness, Workshop Manual |
| Circuit Diagram and Harness | 2 | Hydraulic Circuit Diagram, Electrical Circuit Diagram, Connectors, Engine Harness, Cab Harness |
| Technical Manual Operational Principle | 3-5 | Introduction |
| General | 6-22 | Specification, Working Ranges, Machine Transportation Dimensions, Component Specification, Component Layout |
| System | 23-52 | Control System, Hydraulic System, Electrical System |
| Component Operation | 53-118 | Pump Device, Swing Device, Control Valve, Pilot Valve, Travel Device |
| Technical Manual Troubleshooting | 119-149 | Safety |
| Operational Performance Test | 150-211 | Operational Performance Tests, Engine Test, Excavator Test, Component Test, Adjustment |
| Troubleshooting | 212-320 | Troubleshooting a, Troubleshooting B, Troubleshooting C, Electrical System Inspection |
| Workshop Manual | 321-370 | General Information |
| Upperstructure | 371-520 | Cab, Counterweight, Main Frame, Pump Device, Control Valve, Swing Device |
| Undercarriage | 521-600 | Swing Bearing, Travel Device, Center Joint, Track Adjuster, Front Idler, Upper and Lower Roller |
| Front Attachment | 601-656 | Cylinder, Boom Cylinder, Arm Cylinder, Bucket Cylinder, Boom Swing Cylinder, Blade Cylinder |
| Engine and Accessory | 657-762 | Engine Specification, Identification, Lubrication, Engine Main Body, Lubricating System, Cooling System, Fuel System, Intake and Exhaust System |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Main relief pressure (Front and swing) | 26.0 MPa (265 kgf/cm2, 3770 psi) | p. 13 |
| Main relief pressure (Travel) | 31.4 MPa (320 kgf/cm2, 4550 psi) | p. 13 |
| Main Pump Flow Rate at 2.0 MPa (20 kgf/cm2) | 60 L/min | p. 157 |
| Pump Control Solenoid Valve current | 400 mA | p. 267 |
| T-Bolt Type Band Clamp tightening torque | 4.4 N·m | p. 366 |
| Worm Gear Type Band Clamp tightening torque | 5.9 to 6.9 N·m | p. 366 |
| Mounting bolts (3) torque | 88 N·m (65 lbf·ft) | p. 393 |
| Hose/pipe connection torque (19 mm) | 29 N·m (21.5 lbf·ft) | p. 393 |
| Clearance between plunger outer diameter and cylinder block inner diameter | 0.060 mm | p. 404 |
| End play between plunger and shoe | 0.2 mm | p. 404 |
| Oil filter capacity | 0.7 L (5/8 Imp qt) | p. 366 |
| Operating Weight | 8100 kg | p. 8 |
Hitachi EX80u Common Problems This Manual Covers
Hitachi EX80u boom and bucket move slowly with weak digging force under load
Check hydraulic oil level and the suction filter before touching the pump. Test relief pressure in the front circuit; spec is 26.0 MPa (265 kgf/cm2), listed on page 156. If pressure is good but speed stays low, measure pump control solenoid current against the 400 mA value on page 267 before condemning components.
Manual Section: Front Attachment System Troubleshooting p. 267All hydraulic functions get weak once the machine warms up under load
Run the pump flow test with oil at operating temperature. A healthy main pump delivers 60 L/min at 2.0 MPa (20 kgf/cm2) per the performance test spec on page 157. If flow falls off when hot, suspect internal pump wear or a restricted suction line, and check the oil for contamination before reassembly.
Manual Section: Operational Performance Test p. 157Hydraulic system noisy and jerky after filter change or hose replacement
Bleed trapped air before running the machine hard. Loosen the tank bleed point, then cycle every cylinder slowly to full stroke at low idle until operation smooths out. Inspect suction side connections for air leaks and retorque worm gear band clamps to 5.9 to 6.9 N·m per page 366, then recheck oil level.
Manual Section: Workshop Manual p. 366Engine cranks but starts hard and blows white smoke in cold weather
Verify the air heater circuit powers up before cranking, then bleed the fuel system at the injection pump. If smoke continues after warm-up, pull the injectors for pop testing and reinstall with nozzle tube nuts torqued to 2.0 to 2.5 kg-m (14 to 18 ft-lb) per page 746. Set valve lash while you are in there.
Manual Section: Engine Troubleshooting ChartMachine mistracks or one side travels slow on level ground
Swap the travel pilot lines side to side; if the slow side follows the swap, the fault is upstream in the pilot circuit, not the travel motor. Test travel relief pressure against the 31.4 MPa (320 kgf/cm2) spec on page 13. Clean or replace the pilot filter element before adjusting anything.
Manual Section: Swing/Travel/Blade System TroubleshootingFrequently Asked Questions
What are the torque specifications for the track shoe mounting bolts on the EX80u?
The track shoe mounting bolts on the EX80u require a tightening torque of 245 N⋅m (25 kgf⋅m, 180 lbf⋅ft). p. 360
What is the standard valve clearance for the engine when hot?
The standard valve clearance for both intake and exhaust valves on the engine when hot is 0.35 mm (0.0138 in). p. 668
How do I bleed air from the hydraulic pump?
To bleed air from the hydraulic pump, remove the air bleeding plug from the top of the pump and fill the housing with hydraulic oil. After filling, start the engine at slow idle, slightly loosen the plug until oil oozes out, and then securely tighten the plug. p. 355
What is the standard tightening torque for the cylinder head bolts?
The cylinder head bolts must be tightened in three stages: first to 4.0-4.5 kg-m (29-33 ft-lb), second to 5.5-6.0 kg-m (40-43 ft-lb), and third by an angular method of 90° ± 10°. p. 693
What is the engine oil pan capacity?
The manual lists the engine oil pan capacity as 10 liters (8-3/4 Imp qt) at the H mark and 8 liters (7 Imp qt) at the L mark (page 663). p. 663
Is this Hitachi EX80u manual a PDF I download?
All 762 pages arrive as one searchable PDF at checkout. Read it at the desk, then take the phone out to the machine.
Can I print a copy of this Hitachi EX80u Service Manual for the shop?
You can. The PDF is unlocked and carries no copy protection, so print the sections you want and keep the file as your backup.
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