Part of the Hitachi Repair Manuals.
This 512-page Hitachi Technical Manual covers the EX27U, EX30U, EX35U, EX29UE, EX32UE and EX36UE excavators in one book: the technical volume up front (p2-180) and the workshop volume behind it (p181-512). It walks the hydraulic system from the pump device and control valve through the swing and travel circuits, gives you the operational performance tests with their standard values, the troubleshooting trees for engine and actuator faults, and the full disassembly, inspection and reassembly of the upperstructure, undercarriage, front attachment and the Isuzu engine. Wiring and hydraulic circuit diagrams close the book (p508-512).
What's Inside This Hitachi EX27U to EX36UE Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 2-13 | Specification (Specifications, Working Ranges and Machine Dimensions for Transportation, Engine Specification, Interchangeability) |
| System | 14-25 | Hydraulic System (Outline, Main Circuit, Pilot Circuit) |
| Component Operation | 26-87 | Pump Device (Outline, Main Pump, Pilot Pump, Horse Power Control Operation) |
| Operational Performance Test | 88-133 | Engine Speed, Travel Speed, Swing Speed, Primary Pilot Pressure, Main Relief Valve Set Pressure, Operational Performance Standard |
| Troubleshooting | 134-180 | Engine System Troubleshooting, Actuator Operating System Troubleshooting, Front Attachment System Troubleshooting, Swing System Troubleshooting, Travel System Troubleshooting |
| General Information | 181-198 | Precautions for Disassembling and Assembling, Tightening Torque Specifications, Torque Chart, Piping Joint, Standard Bolt Torques |
| Upperstructure | 199-277 | Canopy, Counterweight, Pump Device, Control Valve, Swing Device, Pilot Valve |
| Undercarriage | 278-333 | Swing Bearing, Travel Device, Center Joint, Track Adjuster, Front Idler, Rollers |
| Front Attachment | 334-385 | Boom Cylinder, Arm Cylinder, Bucket Cylinder, Blade Cylinder, Swing Cylinder |
| Engine | 386-507 | General Information, Disassembly, Inspection and Repair, Lubrication System, Cooling System, Fuel System |
| All Diagrams | 508-512 | Electrical Circuit Diagram, Hydraulic Circuit Diagram, Component Legend |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| EX27u, 29uE | ||
| Engine | ISUZU 16.9 kW/2450 min⁻¹ (23 PS/2450 rpm) | p. 4 |
| Operating Weight, Canopy (EX27U/EX30U) | 2850 kg | p. 4 |
| All Models | ||
| Track Adjuster | 1 to 1.5 turns counterclockwise | p. 87 |
| Fuel injection pressure variation per shim 0.1 mm | 206 kPa (2.1 kgf/cm², 30 psi) | p. 95 |
| Main relief valve adjusting screw turn (EX30U) | 4 mm | p. 120 |
| Main relief valve lock nut torque (EX30U) | 20 +3/-0 N·m (2 +0.3/-0 kgf·m, 14.5 +2.2 -0 lbf·ft) | p. 120 |
| Coolant temperature for overheat indicator | above 110 ± 2 °C(230 ± 35 °F) | p. 167 |
| Tightening Torque for Union Nut (19 mm wrench size) | 59 N·m (6, 44 kgf·m, lbf·ft) | p. 196 |
| Tightening Torque for Union Nut (22 mm wrench size) | 98 N·m (10, 72 kgf·m, lbf·ft) | p. 196 |
| Intake and Exhaust Valve Clearance (cold) | 0.20 ± 0.05 (0.008 ±0.002) mm (in.) | p. 407 |
| 27u, 29uE | ||
| Track adjuster weight | 9.1 kg (20 lb) | p. 320 |
| EX30u, 32uE | ||
| Operating Weight, Canopy (EX35U/EX36UE) | 3100 kg | p. 5 |
Hitachi EX27U to EX36UE Common Problems This Manual Covers
Hitachi EX30U engine stuck at full throttle, idle speed control unresponsive to throttle dial input
Check the ECM control box wiring plug for corrosion and inspect the idle speed sensor connector in the Electrical System Inspection section. Verify a steady 5V reference signal at the sensor plug; a dropped or fluctuating voltage means a bad sensor or wiring fault, not the ECM itself. Clean and reseat all terminals before condemning the control box.
Manual Section: Electrical System InspectionOverheating after operating in mud or deep water, temperature gauge segments climb rapidly
Remove debris packed around the oil cooler core and radiator fins immediately, then inspect all hoses for kinks or collapse. Check the coolant temperature gauge; it trips above 110 ± 2°C (230 ± 35°F) per page 167. Torque any loose oil-cooler flange bolts, flush the system, and refill with clean coolant before restarting.
Manual Section: Malfunction of Coolant Temperature Gauge p. 167Hard starting with white smoke from exhaust, especially in cold or damp weather
Check the fuel filter first; it's flagged as a common clogged component on page 166 for hard starting and white smoke symptoms. Clean or replace the filter and bleed air from the fuel lines. Test each glow plug for continuity, and inspect injection pump timing if starting stays hard after the filter is clear.
Manual Section: Engine System Troubleshooting p. 166Front attachment cylinders drift or leak down heavily when boom, arm, or bucket sit idle
Inspect all hose fittings and union nuts on the front attachment circuit for weeping oil causing cylinder drift. A 19 mm union nut fitting should be torqued to 59 N·m (44 lbf·ft) per the torque specification chart on page 196. Replace any hose showing a kink or bulge, then reseal the fitting rather than just tightening it further.
Manual Section: Front Attachment System Troubleshooting p. 196Machine mistracks or pulls to one side, uneven travel speed left to right
Inspect the track adjuster and tension seals first for wear, leakage, or a stuck grease cylinder. Back off the adjuster 1 to 1.5 turns counterclockwise per the track adjuster procedure on page 87 to relieve grease pressure, then repack it. Retest tracking on level ground before returning the machine to heavy work.
Manual Section: Travel System Troubleshooting p. 87Frequently Asked Questions
What are the torque specifications for the Hitachi EX35U travel device mounting bolt?
For the EX35U and EX36UE models, the travel device mounting bolt should be tightened to 128 N·m (13 kgf·m, 94 lbf·ft). This specification is found in the standard torque chart for machine bolts and nuts. p. 306
How do I adjust the main relief valve pressure for a Hitachi EX30U?
To adjust the main relief valve pressure for EX30U, EX32UE, EX35U, EX36UE models, turn the adjusting screw. A 1/4 turn of the screw will change the pressure by 2.9 MPa (30 kgf/cm², 430 psi). Ensure to recheck the set pressure after adjustment. p. 120
How do I bleed air from the hydraulic system after maintenance?
After hydraulic oil is drained or components replaced, remove the air bleeding plug from the top of the pump and fill the housing with hydraulic oil. Temporarily tighten the plug, start the engine at slow idle, then slightly loosen the plug until oil oozes out. For the hydraulic circuit, operate each cylinder, swing motor, and travel motor evenly under light loads for 10 to 15 minutes to bleed air. p. 184
What is the total engine oil capacity for the 3LD1 engine?
The total engine oil capacity for the 3LD1 engine is approximately 6.8 liters. This specification is listed in the main data and specifications for the engine.
What are the standard cold valve clearances for the engine's intake and exhaust valves?
The standard cold valve clearance for both intake and exhaust valves is 0.20 mm for the 3LA1, 3LB1, and 3LD1 engine models. This measurement is crucial for proper engine operation. p. 94
What do I get after purchasing this Hitachi EX27U & variants manual?
Immediate download of the complete 512-page searchable Technical Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Are there any print restrictions on this Hitachi EX27U & variants manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
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