Troubleshooting a Dead Track on the John Deere 850C Crawler Dozer

[MikePhua]

Introduction
The John Deere 850C Crawler Dozer, produced during the late 1990s and early 2000s, is renowned for its robust performance in various construction and earthmoving tasks. However, like any complex machinery, it is susceptible to issues that can hinder its operation. One such problem is the occurrence of a "dead track," where one side of the dozer fails to move, affecting the machine's maneuverability and efficiency.
Understanding the Dead Track Issue
A "dead track" refers to a scenario where one of the dozer's tracks becomes unresponsive, either failing to move entirely or moving erratically. This issue can arise from several underlying causes, often related to the hydraulic system, electronic controls, or mechanical components.
Common Causes of a Dead Track

1. Hydraulic System Failures
   The hydraulic system is crucial for the movement of the tracks. Issues such as low hydraulic fluid levels, air in the system, or failing hydraulic pumps can lead to inadequate pressure, causing one track to become unresponsive. For instance, a user reported a dead left track on their 850C dozer, with manual overrides failing to activate movement. Upon further inspection, it was found that the hydraulic system's charge pressure was insufficient, preventing proper track operation.
   
2. Electronic Control Problems
   The 850C dozer utilizes electronic control modules (ECMs) to manage various functions, including track movement. Fault codes such as F437 and F465 can indicate issues with sensors or communication between components. For example, code F437 relates to the fuel temperature sensor, while F465 pertains to the steering sensor. These faults can disrupt the signals necessary for track movement.
   
3. Mechanical Component Failures
   Mechanical issues, such as worn-out sprockets, idlers, or track rollers, can impede track movement. Over time, these components may wear down, leading to misalignment or increased friction, which can cause one track to lag or become completely immobile.
   

Diagnostic Steps
To accurately diagnose and resolve a dead track issue on the John Deere 850C dozer, consider the following steps:

1. Check Hydraulic Fluid Levels and Condition
   Ensure that the hydraulic fluid is at the recommended levels and is clean. Contaminated or low-quality fluid can affect the system's performance.
   
2. Inspect Hydraulic Components
   Examine the hydraulic pumps, valves, and lines for signs of wear, leaks, or damage. Any compromised components should be repaired or replaced promptly.
   
3. Verify Electronic Connections and Sensors
   Inspect the wiring harnesses and connectors for corrosion or loose connections. Test the sensors and control modules for proper functionality using diagnostic tools.
   
4. Examine Mechanical Components
   Check the condition of the sprockets, idlers, and track rollers. Look for signs of wear or damage that could impede track movement.
   

Preventive Maintenance Tips
To minimize the risk of encountering a dead track issue in the future:

• Regularly Inspect Hydraulic System
  Perform routine checks on the hydraulic fluid levels and condition. Replace the fluid as recommended by the manufacturer.
  
• Monitor Electronic Systems
  Use diagnostic tools to regularly check for fault codes and address any issues promptly.
  
• Maintain Mechanical Components
  Regularly inspect and maintain the track components, ensuring they are properly lubricated and free from debris.
  

Conclusion
A dead track on the John Deere 850C Crawler Dozer can stem from various issues, including hydraulic system failures, electronic control problems, and mechanical component wear. By systematically diagnosing the problem and adhering to preventive maintenance practices, operators can ensure the longevity and reliability of their equipment. Addressing these issues promptly not only restores the dozer's functionality but also enhances safety and productivity on the job site.