Is the Komatsu PC128UU a Good Investment for Farm and Utility Work

[MikePhua]

The Komatsu PC128UU and Its Unique Design
The Komatsu PC128UU is a compact tail-swing excavator developed primarily for the Japanese domestic market, later exported globally through both official and grey market channels. Introduced in the mid-1990s, the PC128UU was designed to operate in tight urban environments, featuring an offset boom and ultra-short tail swing radius. This configuration allows the machine to work close to walls, buildings, and trenches without risking counterweight collision.
Komatsu, founded in 1921, has long been a leader in hydraulic excavator innovation. By the time the PC128UU was released, the company had already established a reputation for smooth hydraulics, durable undercarriages, and operator-friendly controls. While the PC128UU was never a high-volume export model, thousands were sold domestically and later re-imported into North America and Australia, often as used grey market machines.
Offset Boom Advantages and Limitations
The offset boom is the defining feature of the PC128UU. It allows the boom to pivot laterally, enabling trenching and digging parallel to structures. This is especially useful in urban demolition, utility trenching, and roadside work. However, the offset boom introduces complexity:

• Additional sensors and control logic to prevent boom-arm collision with the cab
  
• Increased wear on pivot bushings and hydraulic lines due to side loading
  
• Electronic depth and grade control systems that may malfunction or be disabled
  

In older units, the boom limit sensors may fail or be bypassed, requiring the operator to manually monitor arm position to avoid contact with the cab. While this is manageable for experienced users, it adds risk in tight quarters.
Grey Market Considerations and Parts Availability
Many PC128UU units in North America are grey market imports—machines originally sold in Japan and later resold abroad. These units may lack English-language decals, operator manuals, or region-specific emissions compliance. However, Komatsu’s global parts network often supports these machines, especially for common components like filters, seals, and hydraulic cylinders.
Challenges include:

• Limited availability of electronic control modules and boom sensors
  
• Difficulty sourcing cab glass and body panels
  
• Incompatibility with some diagnostic tools used by local dealers
  

Operators should verify serial numbers and consult with Komatsu parts distributors before purchasing. In some cases, parts from similar models like the PC120 or PC138 can be adapted with minor modifications.
Performance and Suitability for Farm Use
For agricultural applications such as tiling, ditch cleaning, and general excavation, the PC128UU offers several advantages:

• Compact footprint with the power of a mid-size excavator
  
• Operating weight around 13,000–14,000 kg, providing traction and breakout force
  
• Bucket breakout force exceeding 9,000 kgf, suitable for hard soils
  
• Reach and depth comparable to larger machines, but easier to transport
  

Its weight and hydraulic strength make it capable of assisting with tasks like pulling stuck tractors or repositioning tile plows. Compared to smaller machines like the PC78 or Bobcat 442, the PC128UU offers more muscle without a significant increase in size.
Anecdote from the Midwest
A farmer in Iowa purchased a 1996 PC128UU for tiling and cleanup work. The machine’s computer-controlled boom limiter was non-functional, but he operated it manually without issue. Over 1,000 hours of use, the excavator proved reliable and powerful enough to assist with tile plow recovery. He ultimately chose it over a PC78 due to its weight and breakout force, despite the older age.
Alternative Models and Comparison
While the PC128UU is a capable machine, buyers may also consider:

• Komatsu PC78: Lighter, easier to transport, but less breakout force
  
• CAT 320B: Larger, more powerful, but harder to maneuver in tight spaces
  
• Deere 200 series: Widely supported, good resale value, but heavier
  

The choice depends on intended use, transport logistics, and availability of backup equipment. For users with access to larger machines from neighbors or fleets, the PC128UU fills a valuable mid-size niche.
Recommendations for Buyers
Before purchasing a PC128UU:

• Inspect boom pivot and offset mechanism for wear or sensor failure
  
• Verify hydraulic function and monitor for drift or slow response
  
• Check for signs of corrosion or frame fatigue, especially in re-imported units
  
• Confirm parts availability with local Komatsu dealers
  
• Test the machine in offset boom mode to assess operator comfort
  

If the electronic limiter is disabled, ensure the operator understands the risk of cab contact and maintains visual awareness during offset digging.
Conclusion
The Komatsu PC128UU is a well-built, compact excavator with the power of a larger machine and the agility of a smaller one. Its offset boom and short tail swing make it ideal for confined workspaces, while its weight and hydraulic force suit farm and utility tasks. Though grey market status and electronic quirks may deter some buyers, experienced operators can extract significant value from this machine. With proper inspection and realistic expectations, the PC128UU remains a smart choice for those seeking versatility without sacrificing strength.