Restoring the Bucket Linkage on the Airman AX15 Mini Excavator

[MikePhua]

The Airman AX15 and Its Manufacturing Legacy
The Airman AX15 is a compact hydraulic excavator produced by Airman, a brand under Hokuetsu Industries Co., Ltd., a Japanese manufacturer established in 1952. While Airman is best known for its air compressors and generators, its mini excavators gained traction in the 1990s and early 2000s, especially in Asia and parts of Europe. The AX15 was designed for tight urban job sites, landscaping, and utility trenching, offering a balance of maneuverability and digging power.
Interestingly, Airman has historically collaborated with larger OEMs such as Hitachi and John Deere, manufacturing mini excavators that share components and design features with those brands. This cross-brand compatibility has allowed some operators to source parts from Deere or Hitachi catalogs when Airman-specific components are unavailable.
Bucket Pins and Sleeves Wear Patterns
One of the most common wear points on older mini excavators like the AX15 is the bucket linkage—specifically the pins and sleeves that connect the bucket to the stick and linkage arms. These components endure constant rotational and lateral stress, especially when the machine is used for prying, compacting, or operating without regular greasing.
Symptoms of wear include:

• Excessive play or “slop” in the bucket movement
  
• Difficulty maintaining grade or fine control
  
• Audible knocking or clunking during operation
  
• Uneven wear on bucket teeth due to misalignment
  

In one case in upstate New York, an AX15 owner discovered that a missing grease fitting had led to dry operation of the bucket sleeve. Over time, the pin wore into an oval shape, and the sleeve developed grooves that compromised the fit. The result was a bucket that wobbled even under light loads.
Repair Options and Machine Shop Considerations
Repairing worn bucket pins and sleeves typically involves removing the bucket and stick assembly and either line boring the bores to accept oversized pins or replacing the sleeves entirely. Line boring is a precision machining process that restores concentricity to worn holes, often using portable boring equipment.
Repair steps:

• Remove bucket and short stick from the machine
  
• Inspect pin diameter and sleeve condition
  
• Determine if sleeves are press-fit or welded
  
• If sleeves are damaged, bore out and install new bushings
  
• If bores are elongated, line bore and fit oversized pins
  

Finding a capable machine shop is critical. Shops must have experience with construction equipment and access to portable boring rigs or CNC mills. In the northeastern U.S., some operators report long wait times due to equipment downtime at local shops, so scheduling ahead is advised.
Parts Sourcing Challenges and Cross-Compatibility
Airman parts for older models like the AX15 can be difficult to source, especially outside Japan. The manufacturer no longer supports some legacy models, and parts manuals are often unavailable. However, due to Airman’s OEM relationships, some pins and bushings from Deere or Hitachi mini excavators may fit with minor modifications.
Sourcing tips:

• Measure pin diameter, length, and shoulder dimensions
  
• Compare with Deere 15 series or Hitachi EX15 equivalents
  
• Contact salvage yards specializing in compact equipment
  
• Consider fabricating custom pins from hardened steel if dimensions are known
  

In Washington State, a technician successfully installed bucket pins from a Deere 17D into an AX15 after confirming the dimensions matched. He used a lathe to slightly modify the shoulder thickness and added grease grooves to improve lubrication.
Manuals and Documentation Workarounds
Operators often struggle to find service or parts manuals for the AX15. Without documentation, identifying part numbers and torque specs becomes guesswork. Some owners have resorted to scanning borrowed manuals and creating PDFs for personal use.
Documentation strategies:

• Reach out to other owners for scanned manuals
  
• Offer to digitize and share manuals in exchange for access
  
• Use exploded diagrams from similar models as reference
  
• Record all measurements and part numbers during disassembly
  

In one case, an IT professional turned excavator owner offered to scan and share a manual for the AX15-2 in exchange for a deposit and shipping coverage. This grassroots approach helped preserve knowledge for a machine no longer supported by the factory.
Hydraulic and Track System Observations
Despite the bucket linkage issues, many AX15 units still have strong hydraulics and well-maintained tracks. The hydraulic system on the AX15 is known for responsive control even at idle, and the track assemblies—often rubber with steel reinforcement—hold up well with proper tensioning.
Maintenance tips:

• Grease all pivot points every 10–20 operating hours
  
• Check track tension monthly and adjust as needed
  
• Inspect hydraulic hoses for abrasion and leaks
  
• Replace missing grease fittings immediately to prevent dry operation
  

In one example, an AX15 with over 3,000 hours still had original tracks and no hydraulic leaks, thanks to consistent maintenance and careful operation.
Conclusion
The Airman AX15 remains a capable and compact excavator, but like many older machines, it requires attention to detail and creative problem-solving. Bucket pin and sleeve wear is a common issue, but with the right machine shop, parts sourcing strategy, and documentation efforts, restoration is entirely feasible. Whether you're a seasoned operator or a first-time owner, understanding the quirks of the AX15 can turn a frustrating repair into a rewarding project.