![Hitachi ZX70-3 ZX70LC-3 ZX70LCN-3 Repair Manual [Excavator]](https://youfixthis.com/wp-content/uploads/2014/12/2019-12-01_15-43-27-300x300.jpg)
Part of the Hitachi Repair Manuals.
This 638-page Hitachi Technical Manual covers the ZX70-3, ZX70LC-3, ZX70LCN-3, ZX75US-3 and ZX85US-3 excavators. The technical volume (p7-230) explains the machine system by system, from the controllers and control system through the pump, swing and travel devices. The troubleshooting volume (p231-638) gives you the performance tests with their standard values, the Monitor Unit and Dr. ZX diagnostic procedures, the ICF data lists, the full MC and engine fault-code tables, symptom-based troubleshooting, and the electrical system inspection with its circuit diagrams.
What's Inside This Hitachi ZX70-3 to ZX85US-3 Manual
| System | Pages | Key Topics |
|---|---|---|
| Technical Manual: Introduction & Scope | 1-6 | To the Reader, Additional References, Manual Composition, Page and Section Numbering, Safety |
| General | 7-40 | Group 1 Specifications, Group 2 Component Layout |
| System | 41-132 | Group 1 Controller, Group 2 Control System, Group 3 Hydraulic System |
| Component Operation | 133-230 | Group 1 Pump Device, Group 2 Swing Device, Group 3 Control Valve, Group 4 Pilot Valve, Group 5 Travel Device, Group 6 Others |
| Troubleshooting Manual: Introduction & Safety | 231-272 | To the Reader, Manual Composition, Safety Precautions, Avoid Injury From Rollaway Accidents, Service Manual Revision Request |
| Performance Test | 273-354 | Group 1 Introduction, Group 2 Standard, Group 3 Engine Test, Group 4 Excavator Test, Group 5 Component Test |
| Troubleshooting: Section Contents | 355-357 | Group Index, Diagnosing Procedure, Monitor Unit, Dr. Zx, Icf, Component Layout, Troubleshooting a and B, Electrical System Inspection |
| Diagnosing Procedure | 358-362 | Introduction, Fault Confirmation, Machine Data Collection |
| Monitor Unit | 363-412 | Outline, How to Use Screens, When an Alarm Is Issued, Contents of Alarms, Time and Maintenance Setting, Monitoring, Service Menu (Built-In Diagnosing System), Controller Version, Keyless Hour Meter |
| Dr. Zx Diagnostic Tool | 413-426 | Outline, Monitoring List, Mc Setup, All Parameter Adjustment, Fault Code Reading, Data Recording |
| Icf (Information Controller) | 427-450 | Outline, List of Daily Report Data, Frequency Distribution Data, Total Operating Hours, Download and Upload of Icf Data, Satellite Communication System, List of Fault Codes |
| Component Layout | 451-466 | Main Component Layout, Electrical System Overview, Monitor and Switches, Controllers and Relays, Engine, Pump Device, Battery, Control Valve, Swing and Travel Devices |
| Troubleshooting a (Fault Codes) | 467-530 | Troubleshooting a Procedure, Mc Fault Code List, Engine Fault Codes, Icf Fault Codes, Corrective Actions |
| Troubleshooting B (Symptom-Based) | 531-616 | Troubleshooting B Procedure, Relationship Between Symptom and Faulty Part, Engine, Hydraulic, Swing, Travel and Electrical Symptoms |
| Electrical System Inspection | 617-638 | Sensor and Switch Inspection, Solenoid Valve Inspection, Controller Connector Inspection, Harness Continuity Checks, Electrical Circuit Diagrams |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Injection Pressure (1st stage) | 16.7 MPa (170 kgf/cm², 2430 psi) | p. 30 |
| Injection Pressure (2nd stage) | 25.0 MPa (255 kgf/cm², 3630 psi) | p. 30 |
| Motor Voltage/Output | 24 V/3.2 kW | p. 29 |
| Fuel Filter | ISUZU 89717254901 | p. 37 |
| Full Flow Filter | β10 > 3.0 | p. 37 |
| Suction Filter | 177 μm (80 mesh) | p. 37 |
| STARTER RELAY Voltage/Current | 24 V | p. 37 |
| Change interval | 500 hours | p. 411 |
| Engine Rated Output | 40.5 kW/2000 min⁻¹ (55 PS/2000 rpm) | p. 29 |
Hitachi ZX70-3 to ZX85US-3 Common Problems This Manual Covers
Hitachi ZX70-3 hydraulic pump grinding noise, bucket and boom lose lifting power under load
Start by checking main relief valve set pressure at the control valve; per page 33 it should read 31.4 MPa (320 kgf/cm², 4560 psi) at 26 L/min flow. If pressure reads low, pull the main pump and inspect the shaft seals for wear or scoring, and check the dump valve for internal bypass.
Manual Section: Hydraulic System p. 33Engine won't start or won't rev up under load, especially in cold weather
Check battery voltage first; it should hold a steady 12 V per page 32 spec, and inspect starter motor draw (24 V/3.2 kW rated). If it starts but won't rev up, pull the fuel filter (ISUZU 89717254901) and replace it, per the 500-hour interval on page 411. Verify injector opening pressure hits 16.7 MPa (2430 psi) per page 30 spec.
Manual Section: Engine System Troubleshooting p. 32Machine overheats during heavy operation, coolant temperature warning climbs steadily on the monitor screen
Check the error code reference for E03 hydraulic oil temperature codes. Clean the radiator and oil cooler fins of debris, verify the air filter isn't clogged, and top off coolant and hydraulic fluid to correct levels. Rated engine output is 40.5 kW at 2000 min⁻¹ per page 29 spec; confirm actual RPM matches that under load.
Manual Section: MC Fault Code TroubleshootingUndercarriage wears quickly, tracks won't rotate evenly or mistrack badly during travel over rough grade
Inspect track tension per the maintenance chart; a sagging track accelerates undercarriage wear and mistracking on rough grade. Check the travel motor for internal leakage and verify pilot pressure supply is steady, since low pilot flow causes uneven response. Pilot pump flow is rated 22 L/min (5.8 gpm) per page 33 spec; service the pump if flow drops below that.
Manual Section: Travel Device p. 33Swing function is sluggish or won't rotate, boom drifts down when idle with pilot lock off
Measure swing bearing play with a dial indicator at the pinion; allowable limit is 2.0 to 3.05 mm per page 278 spec, and shim or replace the bearing beyond that. For boom drift, inspect the dump valve and holding valve for leakage past the poppet; a worn dump valve lets the boom settle under its weight at idle.
Manual Section: Swing Device p. 278Frequently Asked Questions
How to reset the error codes on a Hitachi ZX70-3 excavator?
To reset error codes, first write down the fault code. Then, delete the fault code once and retry self-diagnosis again as described in the troubleshooting procedure on page 360. p. 360
How to reset the service hour counter on a Hitachi ZX70LC-3?
To reset the service hour counter for a maintenance item, work through to the interval ON/OFF setup screen and push key 5. Confirm the reset, and the value of remaining hours will be reset to that of the change interval, with the previous change date/hour updated to the current date and time. p. 385
What are the replacement specifications for the Fuel filter?
The replacement interval for the Fuel Filter is 500 hours. This setting can be managed through the Monitor Unit's maintenance settings. p. 411
What is the valve clearance for the engine?
The valve clearance for both intake and exhaust is 0.4 mm when the engine is cold. This measurement should be performed with the engine in a cold state. p. 277
What is the standard nozzle injection pressure?
The standard nozzle injection pressure is 16.7 MPa (170 kgf/cm², 2430 psi). This pressure is measured using a nozzle tester after installation. p. 277
What format is this Hitachi ZX70-3 & variants manual in?
You get a 638-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Can I print specific sections of this Hitachi ZX70-3 & variants manual?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
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