Komatsu PC120, PC120LC-6 Hydraulic Excavator Operation and Maintenance Manual (SEAM063601T)
On a PC120 or PC120LC-6 that’s digging foundations, loading trucks, or trenching in mud and rock, this Operation and Maintenance Manual is what I keep handy to keep the machine earning. It walks you through the daily and periodic checks so you can spot loose track components, sluggish hydraulics, or overheating issues before they sideline the excavator. If a boom cylinder starts to feel weak or cycle times slow down, I use this manual to verify the basic adjustments and routine service steps before calling in heavier diagnostics.
Applications & Use Cases
- Set up a maintenance rhythm so filters, pins, and wear parts are checked and serviced before they fail on a job.
- Trace early hydraulic issues by following the recommended inspection order for leaks, contamination, or abnormal heat.
- Inspect undercarriage and swing gear methodically to catch uneven wear, loose bolts, or misalignment.
- Plan downtime by grouping upcoming services and greasing points around your work schedule.
- Train new operators on correct warm-up, shutdown, and daily walk-around so they don’t abuse the machine.
FAQ
Q: Can I keep this manual on a tablet in the cab?
A: Yes, it’s practical to use digitally; you can zoom diagrams and search terms while you’re right at the machine.
Q: Is it worth printing parts of it?
A: I’d print the inspection checklists and service routines and keep them in a binder that can live in the service truck.
Safety Note
Always lock out controls, relieve system pressure, and secure attachments before performing any inspection or service.
📘 Show Index
Komatsu PC120, PC120LC-6 Hydraulic Excavator Index:
- COVER
- 1. FOREWORD
- 2. SAFETY INFORMATION
- 3. INTRODUCTION
- 4. LOCATION OF PLATES, TABLE TO ENTER SERIAL NO. AND DISTRIBUTOR
- 5. CONTENTS
- SAFETY
- 6. GENERAL PRECAUTIONS
- 7. PRECAUTIONS DURING OPERATION
- 7.1 BEFORE STARTING ENGINE
- 7.2 AFTER STARTING ENGINE
- 7.3 TRANSPORTATION
- 7.4 BATTERY
- 7.5 TOWING
- 7.6 BUCKET WITH HOOK
- 8. PRECAUTIONS FOR MAINTENANCE
- 8.1 BEFORE CARRYING OUT MAINTENANCE
- 8.2 DURING MAINTENANCE
- 9. POSITION FOR ATTACHING SAFETY LABELS
- OPERATION
- 10. GENERAL VIEW
- 10.1 GENERAL VIEW OF MACHINE
- 10.2 GENERAL VIEW OF CONTROLS AND GAUGES
- 11. EXPLANATION OF COMPONENTS
- 11.1 MACHINE MONITOR
- 11.2 SWITCHES
- 11.3 CONTROL LEVERS, PEDALS
- 11.4 CEILING WINDOW
- 11.5 FRONT WINDOW
- 11.6 DOOR LOCK
- 11.7 CAP, COVER WITH LOCK
- 11.8 HOT/COOL BOX
- 11.9 LUGGAGE BOX
- 11.10 ASHTRAY
- 11.11 AIR CONDITIONER
- 11.12 CAR RADIO
- 11.13 ELECTRIC POWER SOURCE
- 11.14 FUSE
- 11.15 FUSIBLE LINK
- 11.16 CONTROLLERS
- 11.17 TOOL BOX
- 11.18 GREASE PUMP HOLDER
- 12. OPERATION
- 12.1 CHECK BEFORE STARTING ENGINE
- 12.2 STARTING ENGINE
- 12.3 OPERATION AND CHECKS AFTER STARTING ENGINE
- 12.4 STOPPING THE ENGINE
- 12.5 MOVING MACHINE OFF
- 12.6 STREETING MACHINE
- 12.7 STOPPING MACHINE
- 12.8 SWINGING
- 12.9 OPERATION OF WORK EQUIPMENT
- 12.10 WORKING MODE SELECTION
- 12.11 HANDLING ACTIVE MODE
- 12.12 PROHIBITIONS FOR OPERATION
- 12.13 PRECAUTIONS FOR OPERATION
- 12.14 PRECAUTIONS WHEN TRAVELING UP OR DOWN HILLS
- 12.15 HOW TO ESCAPE FROM MUD
- 12.16 WORK POSSIBLE USING HYDRAULIC EXCAVATOR
- 12.17 REPLACEMENT AND INVERSION OF BUCKET
- 12.18 PARKING MACHINE
- 12.19 CHECK AFTER STOPPING ENGINE
- 12.20 CHECK AFTER DAILY WORK
- 12.21 LOCKING
- 12.22 HANDLING ROAD LINER (ROAD LINER ONLY)
- 13. TRANSPORTATION
- 13.1 LOADING, UNLOADING WORK
- 13.2 PRECAUTIONS FOR LOADING
- 13.3 PRECAUTIONS FOR TRANSPORTATION
- 14. COLD WEATHER OPERATION
- 14.1 PRECAUTIONS FOR LOW TEMPERATURE
- 14.2 PRECAUTIONS AFTER COMPLETION OF WORK
- 14.3 AFTER COLD WEATHER
- 15. LONG-TERM STORAGE
- 15.1 BEFORE STORAGE
- 15.2 DURING STORAGE
- 15.3 AFTER STORAGE
- 15.4 STARTING MACHINE AFTER LONG-TERM STORAGE
- 16. TROUBLESHOOTING
- 16.1 WHEN MACHINE RUNS OUT OF FUEL
- 16.2 PHENOMENA THAT ARE NOT FAILURES
- 16.3 METHOD OF TOWING MACHINE
- 16.4 USING METHOD FOR LIGHT-WEIGHT TOWING HOOK
- 16.5 PRECAUTIONS ON PARTICULAR JOBSITES
- 16.6 IF BATTERY IS DISCHARGED
- 16.7 OTHER TROUBLE
- MAINTENANCE
- 17. GUIDES TO MAINTENANCE
- 18. OUTLINES OF SERVICE
- 18.1 HANDLING OIL, FUEL, COOLANT, AND PERFORMING OIL CLINIC
- 18.2 OUTLINE OF ELECTRIC SYSTEM
- 18.3 OUTLINE OF HYDRAULIC SYSTEM
- 19. WEAR PARTS LIST
- 20. RECOMMENDED FUEL, COOLANT, AND LUBRICANT
- 20.1 USE OF FUEL, COOLANT AND LUBRICANTS ACCORDING TO AMBIENT TEMPERATURE
- 20.2 RECOMMENDED BRANDS, RECOMMENDED QUALITY FOR PRODUCTS OTHER THAN KOMATSU GENUINE OIL
- 21. STANDARD TIGHTENING TORQUES FOR BOLTS AND NUTS
- 21.1 INTRODUCTION OF NECESSARY TOOLS
- 21.2 TORQUE LIST
- 22. PERIODIC REPLACEMENT OF SAFETY CRITICAL PARTS
- 23. MAINTENANCE SCHEDULE CHART
- 23.1 MAINTENANCE SCHEDULE CHART
- 24. SERVICE PROCEDURE
- 24.1 INITIAL 250 HOURS SERVICE
- 24.2 WHEN REQUIRED
- 24.3 CHECK BEFORE STARTING
- 24.4 EVERY 50 HOURS SERVICE
- 24.5 EVERY 100 HOURS SERVICE
- 24.6 EVERY 250 HOURS SERVICE
- 24.7 EVERY 500 HOURS SERVICE
- 24.8 EVERY 1000 HOURS SERVICE
- 24.9 EVERY 2000 HOURS SERVICE
- 24.10 EVERY 4000 HOURS SERVICE
- 24.11 EVERY 5000 HOURS SERVICE
- SPECIFICATIONS
- OPTIONS, ATTACHMENTS
- 26. GENERAL PRECAUTIONS
- 26.1 PRECAUTIONS RELATED FOR SAFETY
- 27. HANDLING BUCKET WITH HOOK
- 27.1 CHECKING FOR DAMAGE TO BUCKET WITH HOOK
- 27.2 PROHIBITED OPERATIONS
- 27.3 PRECAUTIONS DURING OPERATIONS
- 28. USING SEAT BELT
- 29. HANDLING CAR HEATER
- 29.1 EXPANATION OF COMPONENTS
- 29.2 PREPARING CAR HEATER
- 30. MACHINES READY FOR ATTACHMENTS
- 30.1 GENERAL LOCATIONS
- 30.2 HYDRAULIC CIRCUIT
- 30.3 OPERATION
- 30.4 HANDLING ACCUMULATOR
- 30.5 LONG-TERM STORAGE
- 31. INTRODUCTION OF OPTIONAL PARTS AND ATTCHMENTS
- 31.1 INTRODUCTION OF OPTIOAL PARTS AND ATTACHMENTS
- 31.2 ATTACHMENT INSTALLATION COMBINATION TABLE
- 31.3 SELECTION OF TRACK SHOES
- 31.4 HANDLING ROAD LINER
- 31.5 HANDLING AUTOMATIC GREASING CONTROLLER
- 32. EXTENDING MACHINE SERVICE LIFE
- 32.1 HYDRAULIC BREAKER
- 32.2 POWER RIPPER
- 32.3 FORK GRAB
- 32.4 GRAPPLE BUCKET
- 32.5 SCRAP GRAPPLE
- 32.6 CRUSHER AND SMASHER
- 32.7 HYDRAULIC PILE DRIVER
- 32.8 HYDRAULIC EXCAVATOR WITH MULTI-PURPOSE CRANE
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