Komatsu PC07‑1 Track Installation and Adjustment

[MikePhua]

Overview of the Komatsu PC07‑1
The Komatsu PC07‑1 is a compact excavator introduced during the late 1980s, designed for tight‑access construction, utility trenching, and small‑scale earthmoving. As one of Komatsu’s early mini‑excavator models, it helped establish the company’s presence in the rapidly growing compact equipment market. During this period, global demand for mini excavators surged, with annual sales across all manufacturers exceeding 100,000 units by the early 1990s. The PC07‑1 contributed to Komatsu’s expansion in North America and Asia, offering a simple hydraulic system, mechanical reliability, and easy field serviceability.
Despite its age, many PC07‑1 machines remain in operation today, especially in rural areas and small contractors’ fleets. Their undercarriage design is straightforward, but track installation and adjustment can be challenging for new owners—especially when tracks repeatedly derail.

Why Tracks Come Off on Older Mini Excavators
Track derailment is common on older compact excavators due to:

• Worn sprockets
  
• Weak or leaking track adjusters
  
• Bent track frames
  
• Loose or stretched rubber tracks
  
• Misalignment caused by debris buildup
  

On the PC07‑1, the small diameter of the idler and sprocket makes proper tension especially important. If tension is too loose, the track can slip off the idler during turns. If too tight, the adjuster may overextend or the track may bind.
Terminology Note 
Idler: The front wheel that guides the track and maintains alignment.
Sprocket: The rear toothed wheel that drives the track.
Track adjuster: A grease‑charged cylinder that pushes the idler forward to tighten the track.
Derailment: When the track slips off the idler or sprocket.

Common Track Installation Challenges
The retrieved content describes a situation where the owner repeatedly slipped tracks off both the idler and the sprocket. This is typical when:

• The track is not fully seated on the sprocket teeth
  
• The idler is not centered
  
• The adjuster is not functioning correctly
  
• The track is worn or stretched beyond service limits
  

A common mistake is assuming that reinstalling the track once solves the problem. In reality, a track that has derailed multiple times often indicates an underlying tension or alignment issue.
A small contractor once shared a similar experience with a PC05, where the track slipped off three times in one day. The root cause was a leaking adjuster that slowly lost grease pressure. Once rebuilt, the track stayed on without further issues.

Proper Track Installation Procedure
Although the PC07‑1 is a small machine, installing a track still requires careful technique:

• Fully retract the track adjuster by releasing grease pressure
  
• Clean the sprocket, idler, and rollers to remove packed mud
  
• Position the track over the sprocket first
  
• Use the boom and blade to lift the machine slightly
  
• Walk the track onto the idler using slow rotation
  
• Re‑pressurize the adjuster with grease until proper tension is achieved
  

Correct tension is achieved when the track sags slightly between the top roller and idler—typically around 10–20 mm for small Komatsu models.

Hydraulic Tank Temperature Concerns
After resolving the track issue, the owner noted that the hydraulic tank felt “unreasonably hot”. Hydraulic oil temperature is a critical factor in excavator performance. Excessive heat can damage seals, reduce oil life, and cause sluggish operation.
However, the response in the retrieved content clarifies that normal hydraulic oil temperature ranges from 122°F to 150°F (50°C to 65°C). At these temperatures, the tank may feel hot to the touch, but this is expected.
A simple way to monitor temperature is to use:

• A candy thermometer (as the owner did)
  
• An inexpensive infrared thermal gun
  

These tools help determine whether the machine is operating within safe limits.

Why Hydraulic Tanks Feel Hot
Hydraulic systems generate heat due to:

• Pump inefficiency
  
• Relief valve bypassing
  
• Continuous flow through control valves
  
• Ambient temperature
  
• Long duty cycles
  

Older machines like the PC07‑1 often run hotter because:

• Pumps have internal wear
  
• Oil coolers may be partially clogged
  
• Hydraulic oil may be old or contaminated
  

A farmer in Alberta once reported that his PC07‑1 ran noticeably cooler after replacing the hydraulic oil with a modern ISO 46 fluid and cleaning the cooler fins.

Maintenance Tips for Track and Hydraulic Systems
To keep the PC07‑1 running reliably:

• Inspect track adjusters for leaks
  
• Replace worn sprockets and idlers
  
• Maintain proper track tension
  
• Clean undercarriage components regularly
  
• Monitor hydraulic oil temperature
  
• Replace hydraulic oil and filters at recommended intervals
  
• Use an infrared thermometer to check pump and tank temperatures
  

These steps significantly reduce the likelihood of track derailment and overheating.

Komatsu’s Legacy in Compact Excavators
Komatsu entered the compact excavator market in the late 1970s, and by the 1990s had become one of the world’s leading manufacturers. The PC07‑1 played a role in this growth by offering a durable, easy‑to‑maintain machine that appealed to small contractors and rental fleets.
Today, Komatsu produces advanced mini excavators with electronic controls, improved cooling systems, and more efficient hydraulic circuits. Yet older models like the PC07‑1 remain valued for their simplicity and low operating costs.

Conclusion
Track installation and adjustment on the Komatsu PC07‑1 require careful attention to tension, alignment, and undercarriage condition. Repeated derailment usually indicates an underlying mechanical issue rather than operator error. Meanwhile, hydraulic tank temperatures around 122–150°F are normal for this machine, and simple tools can help verify safe operation.
With proper maintenance and understanding of its systems, the PC07‑1 continues to serve as a reliable compact excavator decades after its introduction.