Part of the Hitachi Repair Manuals.
Wrenching on a Hitachi EX750-5 or EX800H-5? This 665-page Hitachi EX750-5, EX800H-5 technical manual PDF walks you through both hydraulic excavators, from the main pump and swing device down to the track adjuster and front attachment cylinders. Inside: full hydraulic schematics, electrical wiring diagrams, and a huge troubleshooting section that traces faults through the control, hydraulic, and electrical systems step by step. You also get operational performance tests for the engine and excavator, plus removal and installation procedures covering the control valve, swing bearing, travel device, and center joint. Set the high relief pressure to 34.3 MPa (4980 psi) and confirm swing speed hits 8.6 rpm on the performance test. No more diagnosing a lazy swing circuit by feel. Bookmarked and text-searchable; type a spec, jump straight to the page, and get the machine digging again.
What's Inside This Hitachi EX750-5, EX800H-5 Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 1-2 | Manual Composition, Additional References, Page Numbering, Safety Alert Symbols, Unit Conversion |
| General | 3-34 | Specifications, Component Specifications, Component Layout |
| System | 35-80 | Control System, Hydraulic System, Electrical System |
| Component Operation | 81-173 | Pump Device, Swing Device, Control Valve, Pilot Valve, Travel Device |
| Operational Performance Test | 174-229 | Engine Test, Excavator Test, Component Test |
| Troubleshooting | 230-398 | Diagnosing Procedure, Troubleshooting a, Troubleshooting B, Troubleshooting C, Electrical System Inspection |
| Upperstructure | 399-542 | Cab, Counterweight, Pump Device, Control Valve, Swing Device, Pilot Valve, Pilot Shut-Off Valve, Shockless Valve |
| Undercarriage | 543-638 | Swing Bearing, Travel Device, Center Joint, Track Adjuster |
| Front Attachment | 639-665 | Front Attachment Cylinder, Cylinder |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Swing Speed | 8.6 min-1 (rpm) | p. 5 |
| Full flow filter nominal filtration rating | 12 µm or less | p. 17 |
| Pilot filter nominal filtration rating | 10 µm | p. 17 |
| Suction filter nominal filtration rating | 177 µm | p. 17 |
| High relief pressure | 34.3 MPa (4980 psi) | p. 114 |
| Low relief pressure | 30.9 MPa (4480 psi) | p. 114 |
| Rocker arm shaft mounting bolts (1) | 157 N⋅m (116 lbf⋅ft) | p. 180 |
| Housing mounting bolts (2) to (7) | 118 N⋅m (87 lbf⋅ft) | p. 180 |
| O-ring Seal Joint (Union Nut 19) | 59 N·m | p. 394 |
| O-ring Seal Joint (Union Nut 22) | 98 N·m | p. 394 |
| Tightening torque for bolts (7) on counterweight | 2750 N·m (280 kgf·m, 2025 lbf·ft) | p. 410 |
| Tightening torque for bolts (1) on counterweight | 390 N·m (40 kgf·m, 290 lbf·ft) | p. 410 |
Hitachi EX750-5, EX800H-5 Common Problems This Manual Covers
Hitachi EX750-5 boom and arm move slowly, bucket has weak digging force after machine warms up
Check main relief pressure first: spec is 30.9 MPa on page 15, with power boost at 34.3 MPa. If pressure tests low, inspect the full flow filter element (12 µm rating, page 17) for contamination before condemning the pump. After any relief adjustment, torque the lock nut to 59 N·m.
Manual Section: Total Actuator System Troubleshooting p. 15Hydraulic pump whines or growls under load, noise worse at high idle
Check hydraulic tank oil level before anything else; cavitation starts with air on the suction side. Inspect the suction filter (177 µm rating, page 17) and every suction line clamp for leaks. Retorque pump hose fittings to spec, 93 N·m on the 27 mm hoses and 265 N·m on the 14 mm hoses, per page 411.
Manual Section: Upperstructure p. 411Swing starts slowly, chatters under load, and the upperstructure drifts when parked on a slope
Measure swing motor drainage at constant maximum speed; anything over 2 L/min (page 226) means internal motor wear. Check swing bearing play too, since the allowable limit is 5.0 mm on page 224. If you adjust swing relief pressure, torque the relief valve lock nut to 49 N·m when finished.
Manual Section: Swing System Troubleshooting p. 226Hydraulic oil temperature climbs into the red during normal digging, cooler fins look clean
Drain a sample and check oil condition first; dark or milky oil overheats fast. Blow out the oil cooler core from the fan side. Replace the full flow filter element (12 µm rating, page 17) if past interval. Verify main relief settings against the 30.9 MPa spec on page 15; a low set valve bypasses constantly and cooks the oil.
Manual Section: Troubleshooting B (Symptoms) p. 17Oil weeping at pump hose fittings and O-ring seal joints after seal replacement
Replace the O-ring every time a joint is opened; never reuse a flattened seal. Lubricate it lightly with clean hydraulic oil before assembly. Torque O-ring seal joint union nuts to spec, 59 N·m for the 19 mm nut and 98 N·m for the 22 mm nut, per page 394. Overtightening extrudes the seal and restarts the leak.
Manual Section: Troubleshooting p. 394Frequently Asked Questions
How do I clear fault codes on the Hitachi EX750-5 or EX800H-5?
To clear fault codes, you must perform a 'Retrial'. For problems with the controllers (PVC and EC), use 'Retrial A' by turning the Dr.EX OFF, turning the key switch OFF for 10 seconds, then turning it back to ON. For sensor-related problems, use 'Retrial B' by leaving the key switch ON, disconnecting the Dr.EX harness for at least one second, and reconnecting it. p. 236
What are the standard valve clearance specifications for the engine?
The standard valve clearance for the engine when cold is 0.35 mm (0.01 in) for the intake valve and 0.68 mm (0.03 in) for the exhaust valve. p. 181
What is the tightening torque for the main pump mounting bolts?
The tightening torque for the main pump mounting bolts is 690 N⋅m (70 kgf⋅m, 506 lbf⋅ft). p. 411
What is the procedure for bleeding air from the hydraulic pump?
Remove the air bleeding plug from the top of the pump and fill the pump housing with hydraulic oil. After filling, temporarily tighten the plug, start the engine, and run at slow idle. Slightly loosen the plug to bleed air until hydraulic oil oozes out, then securely tighten the plug. p. 386
What is the tightening torque for the swing bearing mounting bolts?
The swing bearing mounting bolts to the undercarriage must be tightened to 1720 N⋅m (175 kgf⋅m, 1270 lbf⋅ft). p. 546
What do I get after purchasing this Hitachi EX750-5 manual?
This is a 665-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Is this Hitachi EX750-5 Technical Manual printable?
No restrictions at all. Print individual pages, full chapters, or the entire manual. The PDF is completely unlocked.
Reviews
There are no reviews yet.