Troubleshooting the John Deere 700J Dozer

[MikePhua]

The John Deere 700J is a popular crawler dozer, known for its durability, power, and versatility. However, like any heavy equipment, it can encounter problems during operation. One common issue that many operators face is when their 700J dozer stops unexpectedly and won’t restart. This can be a frustrating situation, especially when working under tight deadlines or challenging conditions. Understanding potential causes of this issue and knowing how to troubleshoot can save time and reduce downtime.
Overview of the John Deere 700J Dozer
The John Deere 700J dozer is part of the Deere and Company lineup of crawler tractors, designed for tough construction and mining applications. It is known for its powerful engine, advanced hydraulic system, and robust frame.

• Engine Type: The 700J is powered by a 6-cylinder, turbocharged diesel engine that delivers approximately 115 horsepower.
  
• Weight: It weighs around 19,500 pounds (8,845 kg), which makes it a mid-range dozer, suitable for a variety of tasks such as pushing dirt, grading, and land clearing.
  
• Hydraulics: Its hydraulic system is designed to provide high flow and pressure, making it efficient in tasks like lifting, pushing, and carrying heavy loads.
  

Despite its strengths, issues like failure to restart can occur and disrupt operations. Let’s dive into some possible causes and solutions to get your John Deere 700J back to work.
Common Causes for Restarting Issues
Several factors could cause the 700J dozer to stop and fail to restart. Understanding these issues can guide troubleshooting efforts:

1. Fuel System Issues
   • Symptoms: Engine cranks but does not start, or it starts and dies shortly after.
     
   • Possible Causes: Clogged fuel filters, air in the fuel lines, or a malfunctioning fuel pump.
     
   • Solution: Start by inspecting the fuel filter and replacing it if clogged. Check the fuel lines for leaks or blockages, and bleed the fuel system to remove any air. If the issue persists, test the fuel pump to ensure it's delivering the proper pressure.
     
2. Battery or Electrical Issues
   • Symptoms: No cranking at all, or cranks slowly.
     
   • Possible Causes: A weak or dead battery, poor connections, or a malfunctioning alternator.
     
   • Solution: Check the battery voltage and connections. Clean any corrosion from the battery terminals and ensure the cables are tightly secured. If the battery is old or damaged, it may need replacing. Additionally, check the alternator to ensure it's charging the battery properly.
     
3. Starter Motor Problems
   • Symptoms: The engine doesn’t turn over, but electrical components such as lights still function.
     
   • Possible Causes: Faulty starter motor or solenoid.
     
   • Solution: Inspect the starter motor and solenoid for signs of wear or damage. If the starter motor is faulty, it may need to be replaced or repaired.
     
4. Ignition System Malfunctions
   • Symptoms: Engine fails to start even with proper fuel and battery power.
     
   • Possible Causes: Worn-out ignition switch, faulty ignition relay, or issues with the ECU (electronic control unit).
     
   • Solution: Test the ignition switch and relay for continuity. If these components are functional, consider diagnosing the ECU for potential faults. A malfunctioning ECU can prevent the engine from starting or running correctly.
     
5. Overheating or Coolant Issues
   • Symptoms: Engine cuts out due to overheating, and restarting may be impossible until the engine cools down.
     
   • Possible Causes: Low coolant levels, blocked radiator, or malfunctioning water pump.
     
   • Solution: Ensure the coolant level is adequate. If the engine has been running hot, allow it to cool completely before attempting to restart. Check the radiator and cooling system for blockages and replace any damaged parts.
     

Detailed Troubleshooting Process

1. Inspect the Fuel System
   • Begin by checking the fuel filters for dirt or debris. Clogged filters are one of the most common causes of a no-start condition.
     
   • Ensure that the fuel lines are free of leaks. If fuel is not reaching the engine properly, there may be air in the system. Bleed the system to remove any trapped air.
     
   • Check the fuel pump to make sure it's functioning. It should deliver the required fuel pressure to the engine.
     
2. Check the Battery and Electrical Connections
   • If the dozer doesn't even crank, check the battery. A dead battery is often the cause of no-start issues. Even if the lights are on, the battery may not have enough charge to start the engine.
     
   • Clean the battery terminals and check for any corrosion. Loose or corroded connections can prevent the starter motor from receiving power.
     
   • If the battery is weak, try jump-starting the machine or replacing the battery entirely.
     
3. Examine the Starter Motor and Solenoid
   • If the battery is functional and the engine cranks slowly or not at all, test the starter motor and solenoid.
     
   • A damaged solenoid can prevent the starter motor from engaging, while worn-out starter components may cause failure to start.
     
4. Inspect the Ignition System
   • Check the ignition switch and relay to ensure they are working properly. If the switch is worn or the relay is damaged, it may prevent the engine from starting.
     
   • In some cases, problems with the ECU can also cause a failure to start. If you suspect the ECU, a diagnostic scan may be needed to identify any fault codes.
     
5. Check for Overheating
   • If the dozer has been operating in hot conditions or for an extended period, the engine may overheat and shut down to protect itself.
     
   • Check the coolant level and ensure the radiator is not blocked. If the engine has overheated, allow it to cool down before attempting to restart.
     

Preventive Maintenance Tips
To prevent restarting issues and extend the life of your John Deere 700J dozer, regular maintenance is essential. Here are some tips to keep your machine running smoothly:

• Fuel System Maintenance: Regularly replace fuel filters and inspect fuel lines for signs of wear or leaks. Keeping the fuel system clean ensures the engine gets a steady supply of fuel.
  
• Electrical System Checks: Test the battery periodically and clean the terminals to prevent corrosion. Check the alternator to ensure it is charging the battery efficiently.
  
• Hydraulic and Cooling System: Ensure the hydraulic system is properly lubricated and the coolant levels are adequate. Regularly check the radiator for blockages and clean as needed.
  
• Engine Oil and Filters: Change the engine oil and replace filters regularly. Clean oil is vital for maintaining engine performance and preventing overheating or wear.
  

Conclusion
If your John Deere 700J dozer stops and won’t restart, the issue could be related to a variety of systems, including fuel, electrical, starter motor, ignition, or cooling. By following the troubleshooting steps outlined above, you can quickly identify the root cause and get your dozer back to work. Regular maintenance, including checking fluid levels, filters, and the battery, can also help prevent future issues.
In the end, being proactive about maintenance and diagnosing problems early can save significant time and money, ensuring your John Deere 700J continues to perform optimally for years to come.