Komatsu PC60-7 Track Chain Repair and Undercarriage Maintenance

[MikePhua]

The Komatsu PC60-7 and Its Compact Excavation Legacy
The Komatsu PC60-7 is a mid-size hydraulic excavator that became a staple in urban construction, utility trenching, and small-scale earthmoving during the early 2000s. With an operating weight around 6 metric tons and powered by a Komatsu 4D95LE diesel engine, the PC60-7 offered a balance of power, reach, and maneuverability. Komatsu, founded in 1921 in Japan, has sold millions of machines worldwide, and the PC60 series contributed significantly to its global footprint in the compact and mid-range excavator market.
The PC60-7 features a conventional tail swing, a variable displacement hydraulic system, and a steel track undercarriage designed for durability in mixed terrain. Like many excavators in its class, the track chain is a wear-intensive component that requires periodic inspection, adjustment, and eventual replacement.
Terminology Notes

• Track Chain: The assembly of steel links, pins, and bushings that form the continuous loop of the excavator’s track.
  
• Master Pin: A removable pin used to split the track chain for removal or installation.
  
• Track Tensioner: A hydraulic or spring-loaded mechanism that maintains proper chain tension.
  
• Carrier Roller: A roller mounted above the track frame that supports the upper portion of the track chain.
  

Symptoms of Track Chain Wear and Failure
Operators may notice several signs indicating track chain issues:

• Excessive slack or sag between rollers
  
• Popping or clunking sounds during travel
  
• Uneven wear on sprockets or idlers
  
• Difficulty maintaining straight travel
  
• Visible cracks or elongation in chain links
  

In one case, a contractor in Sichuan Province reported that his PC60-7 began veering left during travel and produced a rhythmic knock. Upon inspection, the left-side track chain had a seized bushing and a cracked link near the master pin. The chain had exceeded its service life and required replacement.
Disassembly and Chain Removal Strategy
Track chain repair begins with safe disassembly:

• Park the machine on level ground and lower the blade or bucket for stability
  
• Release track tension by bleeding the grease from the tensioner fitting
  
• Rotate the chain until the master pin is accessible
  
• Use a hydraulic press or pin removal tool to extract the master pin
  
• Walk the chain off the sprocket and idler using a pry bar or excavator arm
  

Some technicians prefer to split the chain on the bottom side for easier access. Always mark the chain orientation to ensure correct reassembly.
Inspection and Component Evaluation
Before installing a new chain, inspect related components:

• Sprockets for hooking or tooth wear
  
• Idlers for flat spots or bearing play
  
• Rollers for leakage or shell damage
  
• Track pads for cracks or bolt looseness
  
• Tensioner rod and seals for corrosion or scoring
  

A technician in Queensland replaced a PC60-7 track chain and discovered the carrier roller had seized, causing premature chain wear. Replacing the roller and adjusting tension improved travel smoothness and extended the new chain’s life.
Installation and Tensioning Procedure
To install the new track chain:

• Position the chain around the sprocket and idler
  
• Align the ends and insert the master pin using a press or sledge and drift
  
• Refill the tensioner with grease until proper sag is achieved (typically 10–20 mm between the bottom roller and chain)
  
• Cycle the track forward and backward to seat the chain
  
• Recheck tension after 30 minutes of operation
  

Avoid over-tensioning, which can accelerate roller and bushing wear. Under-tensioning may cause derailment or pad damage.
Preventive Maintenance and Service Intervals
To extend track chain life:

• Clean tracks daily to remove mud and debris
  
• Inspect tension weekly and adjust as needed
  
• Replace worn pads or bolts promptly
  
• Grease tensioners and carrier rollers monthly
  
• Monitor travel performance and fuel efficiency
  

Fleet managers often log undercarriage hours separately from engine hours. A rental company in Malaysia reduced track failures by 40% after implementing a biweekly undercarriage inspection protocol.
Recommendations for Technicians and Owners

• Keep a master pin removal tool and press in the service truck
  
• Stock spare track pads and bolts for field repairs
  
• Document chain installation date and tension settings
  
• Train operators to avoid sharp turns on hard surfaces
  
• Use OEM or high-quality aftermarket chains with hardened bushings
  

Conclusion
Track chain repair on the Komatsu PC60-7 is a critical maintenance task that directly affects machine mobility, fuel efficiency, and jobsite productivity. With proper disassembly, inspection, and installation techniques, technicians can restore undercarriage integrity and prevent costly downtime. The PC60-7 remains a reliable workhorse when its tracks are kept in top condition—a reminder that even the strongest machines rely on the smallest links to keep moving forward.