Removing the Track Tension Cylinder on a Bobcat T320

[MikePhua]

Bobcat’s Compact Track Loader Evolution
Bobcat, founded in North Dakota in the 1950s, revolutionized compact equipment with its skid-steer loaders. By the early 2000s, the company had expanded into compact track loaders, offering machines with increased traction and reduced ground pressure. The T320, part of Bobcat’s high-performance track loader series, was introduced to meet the demands of grading, land clearing, and heavy-duty material handling.
With an operating weight of approximately 4,500 kg and a turbocharged diesel engine producing around 90 horsepower, the T320 was built for power and precision. Its undercarriage features a torsion suspension system and a hydraulic track tensioning mechanism, which includes a grease-filled tension cylinder that maintains proper track alignment and tension.
Understanding the Track Tension Cylinder Function
The track tension cylinder is a critical component in the undercarriage system. It uses hydraulic grease pressure to push an idler wheel forward, tightening the rubber track. This system allows for easy adjustment and helps prevent track derailment, premature wear, and loss of traction.
Key components include:

• Tension cylinder body
  
• Grease fitting and relief valve
  
• Idler wheel and mounting bracket
  
• Cylinder rod and seal assembly
  
• Track frame housing
  

Over time, the cylinder may leak, seize, or lose pressure, requiring removal and replacement or resealing.
Symptoms of Cylinder Failure
Operators may notice:

• Track sagging or excessive slack
  
• Grease leaking from the cylinder housing
  
• Difficulty maintaining tension after adjustment
  
• Idler wheel movement restricted or uneven
  
• Track derailing during turns or under load
  

In one forestry operation in Oregon, a T320 began throwing its track during sidehill grading. The issue was traced to a failed seal in the tension cylinder, which allowed grease to escape and the idler to retract under load.
Terminology Notes

• Idler Wheel: A non-powered wheel that guides and tensions the track.
  
• Grease-Filled Cylinder: A hydraulic cylinder pressurized by grease rather than fluid, used for slow, controlled movement.
  
• Relief Valve: A valve that allows grease to escape during maintenance or pressure release.
  
• Track Frame: The structural housing that supports the undercarriage components.
  
• Tension Rod: The internal piston that pushes the idler forward to tighten the track.
  

Removal Procedure and Safety Precautions
Removing the tension cylinder requires careful preparation:

• Park the machine on level ground and relieve track tension by loosening the grease relief valve
  
• Remove the track from the idler side using pry bars and a helper if needed
  
• Support the idler wheel with a jack or cribbing to prevent sudden movement
  
• Unbolt the cylinder from the track frame and idler bracket
  
• Inspect mounting surfaces for wear or deformation
  
• Clean all grease residue and prepare for reinstallation or replacement
  

Safety tips:

• Wear eye protection when releasing grease pressure
  
• Use proper lifting tools to support heavy components
  
• Avoid placing hands near pinch points during track removal
  
• Dispose of old grease in accordance with environmental regulations
  

In one rental fleet in Texas, a technician was injured when a pressurized cylinder was removed without relieving grease pressure. After that incident, the company mandated pressure checks and added warning labels to all machines.
Reinstallation and Preventive Maintenance
To reinstall:

• Position the new or rebuilt cylinder and align mounting holes
  
• Torque bolts to manufacturer specifications
  
• Reinstall the track and ensure proper alignment
  
• Pump grease into the fitting until the track deflects ~1 inch under moderate pressure
  
• Cycle the machine to verify tension stability
  

Preventive measures:

• Check track tension weekly during active use
  
• Inspect grease fittings and relief valves for leaks
  
• Replace seals every 2,000 hours or during undercarriage service
  
• Clean track frame and idler area to prevent debris buildup
  
• Monitor track wear and adjust tension as needed
  

In one grading crew in Florida, implementing a monthly undercarriage inspection program reduced track failures by 50% and extended cylinder life by 30%.
Final Thoughts
The track tension cylinder on the Bobcat T320 is a small but vital part of the machine’s performance and reliability. When it fails, the consequences ripple through traction, stability, and safety. With careful removal, proper reinstallation, and consistent maintenance, operators can keep their machines running smoothly across terrain and seasons. In compact track loaders, tension isn’t just mechanical—it’s the balance between control and chaos.