Part of the Hitachi Repair Manuals.
Wrenching on a Hitachi ZX27U-3, ZX30U-3, or ZX35U-3? This 779-page Technical Manual PDF (OEM #T1ND-E) handles the whole mini excavator family, F variants included. Inside: hydraulic schematics with full circuit routing, factory wiring diagrams, and a heavy troubleshooting block split into diagnosing procedures A through C plus electrical system inspection. You also get operational performance test standards for engine, excavator, and component checks, then complete workshop teardowns covering the pump device, swing device, control valve, travel motors, and the undercarriage down to the track adjuster and rollers. Fill the radiator with 2.4 L of coolant and the oil cooler with 1.0 L; swap the air element when the restriction indicator hits -6.23 kPa. Your machine is stuck in the mud, and forum threads won't unstick it. Bookmarked by section; pull it up on your phone at the machine and start wrenching.
What's Inside This Hitachi ZX27–ZX35 Series Manual
| System | Pages | Key Topics |
|---|---|---|
| Technical Manual | 1-4 | Introduction, Additional References, Manual Composition, Page Number |
| Safety | 5-38 | Recognize Safety Information, Understand Signal Words, Follow Safety Instructions, Prepare for Emergencies, Wear Protective Clothing, Protect Against Noise, Inspect Machine |
| General | 39-72 | Specifications, Component Layout, Component Specifications |
| System | 73-130 | Control System, Hydraulic System, Electrical System |
| Component Operation | 131-212 | Pump Device, Swing Device, Control Valve, Pilot Valve, Travel Device, Others |
| Operational Performance Test | 213-270 | Introduction, Standard, Engine Test, Excavator Test, Component Test, Adjustment |
| Troubleshooting | 271-400 | Diagnosing Procedure, Troubleshooting a, Troubleshooting B, Troubleshooting C, Electrical System Inspection |
| Workshop Manual | 401-470 | General (Precautions for Disassembling and Assembling, Tightening, Painting, Bleeding Air From Hydraulic Oil Tank, Floor-Tilting Device) |
| Upperstructure | 471-620 | Canopy and Cab, Counterweight, Pump Device, Control Valve, Swing Device, Pilot Valve, Solenoid Valve |
| Undercarriage | 621-698 | Swing Bearing, Travel Device, Center Joint, Track Adjuster, Front Idler, Upper and Lower Roller, Track |
| Attachment | 699-779 | Removal and Installation of Front Attachment, Front Attachment Weight, Installation of Front Attachment, Maintenance Standard, Side Cutter, Point |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Radiator Capacity | 2.4 L | p. 62 |
| Oil Cooler Capacity | 1.0 L | p. 62 |
| Engine Oil Filter | 20 μm (Nominal) | p. 68 |
| Air Filter (with mechanical indicator) | -6.23 kPa | p. 68 |
| Fuel Filter | 5 μm (Nominal) | p. 68 |
| Travel device mounting bolts (5) torque | 110 Nm | p. 627 |
| Cover (3) bolts (2) torque | 50 Nm | p. 628 |
| Hose connection torque (19 mm) | 29.5 Nm | p. 627 |
| Hose connection torque (22 mm) | 39 Nm | p. 627 |
| Upper Roller Standard A | 100 mm (3.94 in) | p. 690 |
| Upper Roller Standard B | 70 mm (2.76 in) | p. 690 |
| Axle Outer Diameter Standard | 25.0 mm (0.98 in) | p. 691 |
Hitachi ZX27–ZX35 Series Common Problems This Manual Covers
Hitachi ZX30U-3 starter does not rotate, one click from the relay, dash lights dim out when cranking
Check the battery before touching the starter. Load test the 55 Ah battery listed on page 62, then clean and tighten both cable ends. Trace the starter relay, fuse box, and key switch circuits with the wiring diagram, and replace the key switch if continuity drops out in the START position.
Manual Section: Engine System Troubleshooting (Starter does not rotate)Engine cranks strong in cold weather but will not fire, white smoke after long cranking
Test the glow plug and air heater preheat circuit first; a dead plug reads open on a simple continuity check. Replace a waxed or plugged fuel filter with the 5 micron nominal element spec shown on page 68, drain water from the separator, and confirm fuel reaches the injection pump before cranking again.
Manual Section: Engine Start Difficulty at Low TemperatureHydraulic hose weeping at travel motor fittings, oil film across track frame after each shift
Wipe the fittings dry, run the travel circuit, and find the exact seep point. Torque 19 mm hose connections to 29.5 Nm and 22 mm connections to 39 Nm per page 627. Replace any hose with chafe through to the braid, re-secure loose clamps, then bleed air from the hydraulic tank following page 401.
Manual Section: Undercarriage p. 627Coolant temperature climbs under load, fan blowing hot air, noticeable power loss by mid morning
Clean the radiator and oil cooler cores with compressed air from the fan side, blowing debris back out the way it came in. Check coolant level cold and refill using the 2.4 L radiator capacity on page 62; the oil cooler holds another 1.0 L. Inspect coolant hoses for soft spots and replace any that collapse under squeeze.
Manual Section: General p. 62Tracks walk off the front idler in tight turns, rollers squealing, undercarriage packed with mud
Dig the mud out of the track frame before measuring anything. Measure lower roller tread diameter: standard is 30.3 mm, replace at the 24.3 mm allowable limit on page 691. Adjust track sag at the track adjuster covered in the Undercarriage section starting on page 621, and torque travel device mounting bolts to 110 Nm.
Manual Section: Undercarriage p. 691Frequently Asked Questions
How do I clear hydraulic pressure on a ZX27U-3 after shutting down?
To release remaining pressure in the hydraulic system, stop the engine and turn the cap on the hydraulic oil tank slowly to release any remaining pressure before removing it. p. 461
What are the replacement specifications for hydraulic hoses and line clamps?
Hoses and clamps should be inspected periodically and replaced if defective. Specifically, fuel hoses, heater hoses, and hydraulic hoses for the boom, arm, and bucket cylinders should be replaced every 2 years. Engine rubber vibration insulators and floor mount rubbers should be replaced every 5 years or 3000 hours, whichever comes first. p. 458
What is the tightening torque for the swing device mounting bolts on a ZX27U-3?
The tightening torque for the swing device mounting bolts (14 mm diameter) is 140 N·m (14 kgf·m, 101 lbf·ft). p. 449
What is the valve clearance specification for the engine?
The valve clearance for both inlet and exhaust valves should be 0.2/0.2 mm when the engine is cool. p. 57
How do I bleed 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 speed. Then, slightly loosen the plug to bleed air until hydraulic oil oozes out, and finally, securely tighten the plug. p. 442
How is this Hitachi ZX27–ZX35 Series Technical Manual delivered?
Immediate download of the complete 779-page searchable Technical Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Can I print specific sections of this Hitachi ZX27–ZX35 Series Technical Manual?
Zero restrictions. The PDF is DRM-free. Print whatever sections you need to take out to the shop. Standard letter or A4 paper works.
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