Takeuchi TB125, TB135, TB145 Compact Excavator Workshop Manual (CG4E005)

These TB125, TB135, and TB145 compact excavators spend their lives in tight construction sites, utility trenches, and landscaping work, where they get knocked around and packed with mud. This workshop manual is what I’d pull out when I need a clear, step‑by‑step path to strip, inspect, and correctly reinstall major components without guessing. For example, if a boom function is weak or jerky, I’d use this manual to trace the issue—from the control valve through the lines to the cylinder—and then verify everything is aligned and sealed properly on reassembly.

Applications & Use Cases

• Planning major repairs like swing motor, travel drive, or boom cylinder removal and reinstallation in the right sequence.
• Tracing hydraulic faults methodically instead of just swapping parts, helping isolate whether it’s a valve, line routing, or actuator issue.
• Setting up inspection routines after a hard hit, to check structural components and mounts before the machine goes back in the trench.
• Verifying adjustments and linkages on controls, pedals, and levers after repairs so the machine responds predictably.
• Confirming torqueing and sealing habits when you button up critical joints to avoid leaks and premature failures.

FAQ

Q: Can I use this manual on a tablet in the field?

A: Yes, it’s practical to keep it on a tablet or laptop so you can zoom in on diagrams and follow procedures right beside the machine.

Q: Is it worth printing parts of this manual?

A: Many techs print just the sections they’re using that day, so pages can be marked up, kept clean with sleeves, and carried under the cab or onto the upper frame.

Safety Note

Always follow the manual’s support, lockout, and pressure‑relief steps before loosening or removing any major component.

Takeuchi TB125, TB135, TB145 Compact Excavator Index:

• FOOT OF THE PAGE
• I . GENERAL
  • Safety Precautions
  • Cautions during Disassembly and Assembly
  • Cautions during Removal and Installation of the Hydraulic Units
  • Cautions during Removal and Installation of Piping
  • Handling of Seals
  • Tightening Torques
• II . SPECIFICATIONS
  • Names of Components
  • Dimensions
  • Specification Tables
  • Mass Tables
  • Recommended Lubricants
  • Types of Crawler Belts
  • Types of Attachments and Their Combinations
  • Service Standards
  • Standards for Judging Performance
• III . MACHINE CONFIGURATION
  • Drive System
  • Slew System
  • Travel System
  • Upper Frame
  • Control System
  • Attachments
  • Hydraulic System
  • Electrical System
  • Proportional Control
  • Air Conditioner System
  • Security System
• IV . HYDRAULIC UNITS
  • Hydraulic Pump (TB125: S/N 12510009-12512125, TB145)
  • Hydraulic Pump (TB125: S/N 12512126-, TB135)
  • Control Valve (TB125, TB135)
  • Control Valve (TB145)
  • Pilot Valve(TB125: S/N 12510003-12514525, TB135: S/N13510004-13514050, TB145: S/N 14510004-14513260)
  • Pilot Valve (TB125: S/N 12514526-, TB135: S/N 13514051-, TB145: S/N 14513261-)
  • Pilot Valve (Swing)
  • Shut-Off Valves
  • Proportional Control Solenoid Valve (TB145)
  • Cylinders
  • Bucket Cylinder for Telescopic Arm (TB145)
  • Tensioning Cylinder
  • Travel Motor (TB125: S/N 12510009- 12514525)
  • Travel Motor (TB125: S/N 12514526-)
  • Travel Motor (TB135)
  • Travel Motor (TB145)
  • Slew Motor (TB125)
  • Slew Motor (TB135)
  • Slew Motor (TB145)
  • Swivel Joint
• V . TROUBLESHOOTING
  • OVERALL MACHINE
  • MACHINE TRAVEL
  • SLEWING
  • BOOM
  • ARM
  • BUCKET
  • BOOM SWING
  • DOZER BLADE
  • AUXILIARY HYDRAULICS
• VI . ENGINE
  • Cover TNE series
  • CONTENTS
  • Cover 3TNV/4TNV series
  • History of Revision
  • PREFACE
  • SAFETY LABELS
  • CONTENTS
  • 1. General
    • 1.1 Engine nomenclature
    • 1.2 Specifications
    • 1.3 Fuel oil, lubricating oil and cooling water
      • 1.3.1 Fuel oil
      • 1.3.2 Lubricating oil
      • 1.3.3 Cooling water
    • 1.4 Engine external views
    • 1.5 Structural description
    • 1.6 Exhaust gas emission regulation
      • 1.6.1 The emission standard in USA
      • 1.6.2 Engine identification
      • 1.6.3 Guarantee conditions for the EPA emission standard
  • 2. Inspection and adjustment
    • 2.1 Periodic maintenance schedule
    • 2.2 Periodic inspection and maintenance procedure
      • 2.2.1 Check before daily operation
      • 2.2.2 inspection after initial 50 hours operation
      • 2.2.3 Inspection every 50 hours
      • 2.2.4 Inspection every 250 hours or 3 months
      • 2.2.5 Inspection every 500 hours or 6 months
      • 2.2.6 Inspection every 1,000 hours or one year
      • 2.2.7 Inspection every 2000 hours or 2 years
    • 2.3 Adjusting the no-load maximum or minimum speed
    • 2.4 Sensor inspection
      • 2.4.1 Oil pressure switch
      • 2.4.2 Thermo switch
    • 2.5 Water leak check in cooling water system
    • 2.6 Radiator cap inspection
    • 2.7 Thermostat Inspection
    • 2.8 Adjusting operation
    • 2.9 Long storage
  • 3. Troubleshooting
    • 3.1 Preparation before troubleshooting
    • 3.2 Quick reference table for troubleshooting
    • 3.3 Troubleshooting by measuring compression pressure
  • 4. Disassembly, inspection and reassembly of engines
    • 4.1 Complete disassembly and reassembly
      • 4.1.1 Introduction
      • 4.1.2 Special service tools
      • 4.1.3 Complete disassembly
      • 4.1.4 Precautions before and during reassembly
      • 4.1.5 Adjusting operation
    • 4.2 Cylinder head: Disassembly, inspection and reassembly
      • 4.2.1 Components (2-valve cylinder head)
      • 4.2.2 Disassembly procedure:
      • 4.2.3 Reassembly procedure:
      • 4.2.4 Servicing points
      • 4.2.5 Parts Inspection and measurement
      • 4.2.6 Valve seat correction
      • 4.2.7 Valve guide replacement
      • 4.2.8 Valve stem seal replacement
    • 4.3 Gear train and camshaft
      • 4.3.1 Components
      • 4.3.2 Disassembly procedure:
      • 4.3.3 Reassembly procedure:
      • 4.3.4 Servicing points
      • 4.3.5 Parts inspection and measurement
      • 4.3.6 Oil seal replacement (Gear case side)
      • 4.3.7 Camshaft bushing replacement
    • 4.4 Cylinder block
      • 4.4.1 Components
      • 4.4.2 Disassembly procedure:
      • 4.4.3 Reassembly procedure:
      • 4.4.4 Servicing points
      • 4.4.5 Parts inspection and measurement
      • 4.4.6 Cylinder bore correction
      • 4.4.7 Piston pin bushing replacement
      • 4.4.8 Oil seal replacement (Flywheel housing side)
  • 5. Lubrication system
    • 5.1 Lubrication system diagram
    • 5.2 Trochoid pump components
    • 5.3 Disassembly (Reverse the procedure below for assembly)
    • 5.4 Servicing points
    • 5.5 Parts Inspection and measurement
      • 5.5.1 Trochoid pump inspection and measurement
    • 5.6 Lube oil filter
      • 5.6.1 Lube oil filter construction
      • 5.6.2 Lube oil filter replacement
  • 6. Cooling system
    • 6.1 Cooling water system
    • 6.2 Cooling water pump components
    • 6.3 Disassembly (Reverse the procedure below for assembly)
    • 6.4 Servicing points
  • 7. Fuel injection pump / Governor
    • 7.1 Introduction
    • 7.2 Fuel injection pump
      • 7.2.1 Fuel system diagram
      • 7.2.2 External view and components
      • 7.2.3 Disassembly procedure:
      • 7.2.4 Assembly procedure
      • 7.2.5 Servicing points
      • 7.2.6 C.S.D. (Cold Start Device)
  • 8. Turbocharger: Disassembly, inspection and reassembly
    • 8.1 Structure and functions
      • 8.1.1 Main specifications
      • 8.1.2 Construction
      • 8.1.3 Structural and functional outline
      • 8.1.4 Components
    • 8.2 Service standards and tightening torque
      • 8.2.1 Service standards
      • 8.2.2 Tightening torque
    • 8.3 Periodic inspection procedure
      • 8.3.1 Periodic inspection intervals
      • 8.3.2 Inspection procedure
      • 8.3.3 Waste gate valve adjustment procedure
    • 8.4 Disassembly procedure
      • 8.4.1 Preparation for disassembly
      • 8.4.2 Inspection before disassembly
      • 8.4.3 Disassembly
    • 8.5 Washing and inspection procedure
      • 8.5.1 Washing
      • 8.5.2 Inspection procedure
    • 8.6 Reassembly procedure
      • 8.6.1 Preparation for reassembly
      • 8.6.2 Reassembly
    • 8.7 Handling after disassembly and reassembly
      • 8.7.1 Instructions for turbocharger installation
    • 8.8 Troubleshooting
      • 8.8.1 Excessively exhaust smoke
      • 8.8.2 White smoke generation
      • 8.8.3 Sudden oil decrease
      • 8.8.4 Decrease in output
      • 8.8.5 Poor (slow) response (starting) of turbocharger
      • 8.8.6 Abnormal sound or vibration
  • 9. Starting motror
    • 9.1 For 4TNV94L/ 98
      • 9.1.1 Specifications
      • 9.1.2 Components
      • 9.1.3 Troubleshooting
      • 9.1.4 Names of parts and disassembly procedure
      • 9.1.5 Inspection and maintenance
      • 9.1.6 Service standards
      • 9.1.7 Assembly
      • 9.1.8 Characteristic test
    • 9.2 For 4TNV106 (T)
      • 9.2.1 Specifications
      • 9.2.2 Congiguration drawing
      • 9.2.3 Troubleshooting
      • 9.2.4 Component names and disassembly procedure
      • 9.2.5 Disassembly procedure
      • 9.2.6 Inspection and maintenance
      • 9.2.7 Assembly
      • 9.2.8 Adjustment
      • 9.2.9 Service standards
    • 9.3 For 3TNV82A to 3/4TNV88
      • 9.3.1 Specifications
      • 9.3.2 Characteristics
      • 9.3.3 Disassembly drawing
      • 9.3.4 Connecting diagram of a starting motor
  • 10. Alternator
    • 10.1 The 40A alternator for 3TNV84 and other models
      • 10.1.1 Components
      • 10.1.2 Specifications
      • 10.1.3 Wiring diagram
      • 10.1.4 Standard output characteristics
      • 10.1.5 Inspection
      • 10.1.6 Troubleshooting
  • 11. Electric wiring
    • 11.1 Electric wiring diagram
    • 11.2 Precaution on electric wiring
      • 11.2.1 Alternator
      • 11.2.2 Starter
      • 11.2.3 Current limiter
      • 11.2.4 Section area and resistance of electric wire
  • 12. Service standards
    • 12.1 Engine tuning
    • 12.2 Engine body
      • 12.2.1 Cylinder head
      • 12.2.2 Gear train and camshaft
      • 12.2.3 Cylinder block
    • 12.3 Lubricating oil system (Trochoid pump)
  • 13. Tightening torque for bolts and nuts
  • Back cover
  • YPD-MP2/YPD-MP4
  • CONTENTS

Takeuchi