Installing Chains and Sprockets on the Fiat-Allis FL5 Track Loader

[MikePhua]

The Fiat-Allis FL5 and Its Mechanical Heritage
The Fiat-Allis FL5 is a compact track loader developed during the late 1970s and early 1980s, a product of the joint venture between Fiat of Italy and Allis-Chalmers of the United States. This collaboration aimed to blend European design efficiency with American ruggedness. The FL5 was designed for light-to-medium earthmoving tasks, offering excellent maneuverability in confined spaces and reliable traction on soft terrain.
Powered by a Fiat 4-cylinder diesel engine producing around 70 horsepower, the FL5 featured a hydrostatic transmission and a sealed undercarriage system. Its compact size made it popular among contractors, municipalities, and agricultural users. Fiat-Allis sold thousands of FL5 units globally before the brand transitioned into Fiat-Hitachi and eventually CNH Industrial.
Track System Overview and Wear Components
The FL5 uses a track-type undercarriage composed of:

• Track chains (also called link assemblies)
  
• Sprockets (drive wheels)
  
• Rollers (carrier and track)
  
• Idlers (front tensioning wheels)
  
• Track shoes (bolt-on pads)
  

Over time, these components wear due to friction, impact, and environmental exposure. Chains elongate, sprocket teeth sharpen or cup, and rollers lose their seals. Replacing chains and sprockets is essential to maintain traction, reduce vibration, and prevent damage to the final drives.
Preparation and Safety Measures
Before beginning the installation process, operators should follow these preparatory steps:

• Park the machine on level ground and block the tracks
  
• Release track tension using the grease valve on the idler
  
• Remove track guards and clean the undercarriage
  
• Inspect final drive seals and bearings for leaks or play
  
• Use lifting equipment rated for at least 1000 kg per side
  

Safety is paramount. Always wear steel-toe boots, gloves, and eye protection. Use cribbing blocks to support the machine if lifting is required. Never work under unsupported tracks or rely solely on hydraulic jacks.
Removing the Old Chains and Sprockets
The removal process involves:

• Loosening track shoe bolts and removing a section to create slack
  
• Breaking the master pin using a hydraulic press or pin punch
  
• Rolling the chain off the sprocket and idler
  
• Unbolting the sprocket from the final drive hub
  
• Inspecting the hub splines and mounting surface
  

In one field case from Ontario, a contractor discovered that the sprocket bolts had seized due to rust. Heating the bolts with a torch and applying penetrating oil allowed removal without damaging the hub. Always use a torque wrench during reinstallation to avoid uneven loading.
Installing New Chains and Sprockets
Installation requires precision and patience:

• Align the new sprocket with the hub and torque bolts to spec (usually 180–220 ft-lbs)
  
• Lay the new chain around the idler and sprocket, ensuring correct orientation
  
• Insert the master pin and secure with a retaining clip or bolt
  
• Reinstall track shoes and torque bolts evenly
  
• Re-tension the track using the grease valve until 1–2 inches of sag remain between the carrier roller and track
  

Track tension is critical. Over-tightening increases wear on rollers and idlers, while under-tightening causes derailing. A properly tensioned track should allow slight flex when pressed by hand.
Troubleshooting and Field Adjustments
Common issues during installation include:

• Misaligned sprocket causing chain binding
  
• Incorrect chain pitch leading to tooth skipping
  
• Master pin not seating due to burrs or misalignment
  
• Excessive noise from dry rollers or worn bushings
  

Solutions include:

• Using emery cloth to clean pin holes
  
• Applying anti-seize compound on sprocket bolts
  
• Lubricating rollers with high-viscosity grease
  
• Rechecking alignment after 10 hours of operation
  

In a case from New Zealand, an FL5 owner reported chain popping after installation. The cause was a mismatched chain pitch—his replacement chain was for a larger FL7 model. After sourcing the correct chain, the issue was resolved.
Maintenance Tips and Longevity Strategies
To extend the life of the new chains and sprockets:

• Clean the undercarriage daily in muddy conditions
  
• Inspect track tension weekly
  
• Grease rollers and idlers monthly
  
• Replace worn track shoes to prevent uneven wear
  
• Avoid high-speed turns on hard surfaces
  

Track chains typically last 1500–2500 hours depending on terrain and maintenance. Sprockets may last longer if replaced with hardened steel variants. Keeping a logbook of service intervals helps anticipate replacements and avoid downtime.
Fiat-Allis Legacy and Market Impact
Fiat-Allis was a major player in the 1970s and 1980s, producing dozers, loaders, and graders for global markets. The FL5 was part of its compact equipment line, competing with machines like the Caterpillar 931 and John Deere 455. Though the brand eventually merged into CNH, many FL5 units remain in service today, especially in Latin America and Eastern Europe.
Collectors and restorers value the FL5 for its mechanical simplicity and robust design. In 2022, a restored FL5 sold at auction in Italy for €14,000, highlighting its enduring appeal. Replacement parts are still available through aftermarket suppliers and vintage equipment networks.
Conclusion
Installing chains and sprockets on the Fiat-Allis FL5 is a rewarding task that restores traction, stability, and operational confidence. With careful preparation, correct parts, and attention to detail, operators can complete the job safely and effectively. Whether grading driveways in Montana or clearing brush in Tuscany, the FL5 continues to prove that good design never goes out of style.