Dealing with a Bent Rollerframe Axle on a Case 850

[MikePhua]

The Case 850 is a reliable crawler dozer known for its performance in tough construction and landscaping environments. However, like all heavy equipment, it can experience mechanical issues over time. One such problem is a bent rollerframe axle, which can cause significant operational difficulties. This article explores the causes, symptoms, and solutions for addressing a bent rollerframe axle on a Case 850.
Understanding the Rollerframe Axle Issue

1. What is the Rollerframe Axle?
   • The rollerframe axle is a critical component in a crawler dozer. It is part of the undercarriage system and supports the rollers and tracks, enabling the machine to move effectively across uneven terrain. A bent axle can result in uneven track wear, reduced machine efficiency, and potential damage to other components.
     
2. Symptoms of a Bent Rollerframe Axle
   • Uneven Track Wear: One of the most noticeable signs of a bent rollerframe axle is uneven or accelerated wear on the tracks. The tracks may also appear to sag or sag unevenly.
     
   • Difficulty in Turning: The dozer may experience difficulty in turning or maneuvering, as the misalignment caused by the bent axle can affect the overall stability of the machine.
     
   • Excessive Vibration: A bent axle can also lead to increased vibration during operation. This may result in a rough ride for the operator and can indicate that the rollers are not aligned properly.
     
   • Unusual Noise: If the rollers are misaligned, they may produce a grinding or clunking noise as they rotate. This noise is a clear indicator of an axle problem.
     

Causes of a Bent Rollerframe Axle

1. Impact from Obstacles
   • The most common cause of a bent rollerframe axle is a hard impact, such as running over large rocks, tree stumps, or debris in the work area. Such impacts can cause the axle to bend, leading to misalignment of the rollers.
     
2. Overloading the Machine
   • If the machine is consistently overloaded beyond its weight capacity, excessive stress can be placed on the undercarriage components, including the rollerframe axle. This can cause it to bend over time.
     
3. Improper Maintenance
   • Lack of regular maintenance, such as neglecting to replace worn-out rollers or lubricating moving parts, can cause uneven wear and stress on the axle. This can gradually lead to bending or distortion.
     
4. Manufacturing Defects
   • In rare cases, a manufacturing defect or design flaw can contribute to a bent axle. This could be due to incorrect material selection or poor-quality welding, leading to weakness in the rollerframe axle.
     

Steps for Fixing a Bent Rollerframe Axle

1. Assessment and Inspection
   • Visual Inspection: The first step in fixing a bent rollerframe axle is to visually inspect the undercarriage components. Look for any visible signs of damage, misalignment, or uneven wear on the tracks and rollers.
     
   • Track Alignment Check: Check the alignment of the tracks and rollers to determine if they are deviating from their normal path. If the tracks are not aligned properly, it is likely that the axle is bent.
     
   • Measure Roller Spacing: Measure the spacing between the rollers to ensure they are all positioned evenly. Any discrepancies in spacing can indicate a bent axle.
     
2. Disassemble the Undercarriage
   • Remove Tracks and Rollers: To access the rollerframe axle, you will need to remove the tracks and rollers. Use the appropriate tools to disassemble the undercarriage carefully, ensuring that no other components are damaged during the process.
     
   • Lift the Machine: Lift the dozer off the ground using a jack or crane to support it safely while working on the axle. Ensure the machine is stable before proceeding with the repair.
     
3. Straightening or Replacing the Axle
   • Straightening the Axle: In some cases, the bent rollerframe axle can be straightened using a hydraulic press or other specialized equipment. This method can be effective if the damage is not severe. However, straightening should only be done if the axle is not cracked or weakened, as it may fail after repair.
     
   • Replacing the Axle: If the axle is severely bent or damaged beyond repair, it is best to replace it with a new or reconditioned part. Ensure that the replacement axle is compatible with your Case 850 and properly aligned during installation.
     
4. Reassembling the Undercarriage
   • Once the axle is repaired or replaced, reassemble the tracks and rollers. Ensure that the rollers are properly aligned and that the tracks are tensioned correctly. Proper tension is critical to avoid further damage to the undercarriage.
     
   • Lubricate the moving parts of the undercarriage to reduce friction and wear. Use the correct type of lubricant as specified in the Case 850's maintenance manual.
     

Preventive Measures

1. Regular Maintenance
   • Regularly inspect and maintain the undercarriage to prevent issues with the rollerframe axle. Check for signs of wear on the rollers, tracks, and axle, and replace components as needed to avoid larger problems.
     
   • Clean the undercarriage frequently to remove dirt, debris, and mud that can accumulate and cause undue stress on the rollers and axle.
     
2. Avoid Overloading
   • Always operate the Case 850 within its rated capacity. Overloading the machine can put excessive stress on the undercarriage, leading to premature wear or even damage to the rollerframe axle.
     
3. Careful Operation
   • Be mindful of the terrain you are working on. Avoid driving over large obstacles or rough surfaces that could cause sudden impacts. Use the machine in a controlled manner to minimize the risk of damaging the undercarriage.
     
4. Use Proper Tracks
   • Ensure that the tracks and rollers are the correct size and type for the job. Using tracks that are too large or too small for the machine can cause misalignment and damage to the rollerframe axle.
     

Conclusion
A bent rollerframe axle on a Case 850 can significantly affect the machine’s performance and safety. Identifying the cause of the problem, whether it’s from an impact, overloading, or improper maintenance, is essential to resolving the issue. By performing a careful inspection, following the necessary repair steps, and taking preventive measures, you can keep your Case 850 in optimal working condition and avoid future undercarriage problems. Proper care and regular maintenance are key to prolonging the lifespan of the machine and ensuring smooth operation on the job site.