Track Tension Problems on the Case 1150 Dozer

[MikePhua]

The Case 1150 and Its Role in Earthmoving History
The Case 1150 crawler dozer was introduced in the 1970s as part of Case Corporation’s expansion into mid-size track-type tractors. Known for its balance of power and maneuverability, the 1150 was widely used in road building, land clearing, and site preparation. With an operating weight of approximately 28,000 pounds and a six-cylinder diesel engine producing around 130 horsepower, the machine offered solid pushing power and a reliable undercarriage system.
Case, founded in 1842 and later merged into CNH Industrial, built the 1150 series to compete with Caterpillar’s D5 and John Deere’s 750 models. Over the years, the 1150 evolved through multiple variants—1150B, 1150C, 1150D, and 1150E—each with refinements in hydraulics, transmission, and operator comfort. Tens of thousands of units were sold globally, and many remain in operation today.
Terminology Clarification

• Track Tensioner: A hydraulic or grease-filled mechanism that pushes the idler forward to tighten the track chain.
  
• Track Idler: A wheel at the front of the track frame that guides the track and receives tension from the adjuster.
  
• Grease Fitting (Zerk): A port used to inject grease into the tensioning cylinder.
  
• Relief Valve: A small valve that releases grease or pressure when servicing the tensioner.
  
• Track Chain: The assembly of links and bushings that wraps around the sprockets, rollers, and idlers.
  

Common Causes of Track Tension Failure
When the track on a Case 1150 cannot be tightened, the issue typically lies within the tensioning system. Symptoms include:

• Excessive sag between the carrier roller and idler
  
• Grease leaking from the adjuster housing
  
• No movement in the idler after pumping grease
  
• Track jumping off during turns or reverse operation
  

The most common causes include:

• Leaking Seal in the Adjuster Cylinder
  Internal or external seal failure allows grease to escape, preventing pressure buildup.
  
• Stuck or Seized Idler
  Rust, debris, or mechanical damage can prevent the idler from sliding forward.
  
• Damaged Relief Valve
  A faulty valve may leak grease immediately after injection, nullifying tension.
  
• Worn Track Components
  Excessive wear in the chain, bushings, or sprockets can create slack beyond the adjuster’s range.
  

In one case from rural Arkansas, a land-clearing crew found their 1150C’s track sagging despite repeated greasing. After removing the adjuster, they discovered the piston seal had split, allowing grease to bypass internally. Replacing the seal restored full tension.
Diagnostic and Repair Steps
To resolve track tension issues:

1. Inspect the Grease Fitting and Relief Valve
   Clean both ports and check for leaks. Replace damaged fittings.
   
2. Pump Grease into the Adjuster
   Use a high-pressure grease gun. Monitor the idler for movement. If none occurs, proceed to disassembly.
   
3. Remove the Track Adjuster Assembly
   Safely block the track and remove the adjuster. Inspect the piston, seals, and cylinder bore.
   
4. Clean and Lubricate the Idler Slide Rails
   Remove rust and debris. Apply anti-seize compound or heavy grease.
   
5. Replace Seals and Reassemble
   Use OEM or high-quality aftermarket seal kits. Torque bolts to spec and test for leaks.
   
6. Check Track Chain Wear
   Measure pin-to-bushing clearance. Replace chain if elongation exceeds manufacturer limits.
   

Preventive Maintenance and Best Practices
To maintain proper track tension:

• Grease the adjuster monthly or every 50 hours of operation
  
• Inspect track sag visually before each shift
  
• Clean mud and debris from the undercarriage daily
  
• Avoid sharp turns on hard surfaces to reduce side loading
  
• Replace worn rollers and sprockets during scheduled service intervals
  

In 2019, a forestry operator in Oregon implemented a weekly undercarriage inspection protocol across his fleet. Over two years, track-related downtime dropped by 45%, and undercarriage life increased by 20%.
Recommendations for Owners and Technicians
If your Case 1150 track won’t tighten:

• Begin with grease fitting and relief valve inspection
  
• Document adjuster movement and grease consumption
  
• Disassemble and inspect the adjuster if tension fails to build
  
• Keep spare seal kits and fittings in your service truck
  
• Train operators to recognize early signs of track slack
  

Conclusion
Track tension problems on the Case 1150 are often caused by seal failure, mechanical obstruction, or component wear. With methodical diagnostics and proper maintenance, the issue can be resolved without major expense. The 1150 remains a dependable workhorse when its undercarriage is kept in good condition. Whether pushing dirt or clearing timber, a properly tensioned track ensures safety, efficiency, and long-term durability.