Troubleshooting the John Deere 135C Blade That Won't Stay Up: Causes and Solutions

[MikePhua]

Introduction: The Importance of Blade Control in Excavators
The John Deere 135C is a highly capable and versatile compact excavator that plays a crucial role in construction, digging, and grading applications. One of its key features is its blade control system, which allows operators to level ground and improve the stability of the machine during operation. However, like any heavy equipment, the John Deere 135C can sometimes experience issues with its blade functionality, such as the blade failing to stay up.
A blade that won’t stay in position can severely affect the machine’s performance and efficiency, especially during grading or leveling work. This issue can arise from several mechanical or hydraulic causes, and identifying the root of the problem is crucial for a timely repair. In this article, we’ll explore the potential causes of this problem and provide solutions to help you get your John Deere 135C back in working order.
Common Causes for a Blade That Won't Stay Up
The John Deere 135C excavator is designed for durability and ease of operation, but like any complex piece of machinery, it can experience problems. Here are the most common reasons why the blade might not stay up and how to troubleshoot each one.

1. Hydraulic System Leaks or Low Fluid
   

Since the blade's lifting function is powered by hydraulics, any issues within the hydraulic system can directly affect its ability to hold the blade up. Hydraulic leaks or insufficient fluid levels are among the most common causes of blade failure.

• Symptoms: The blade moves slowly or won't stay up when the operator attempts to raise it.
  
• Possible Causes: Leaking hydraulic hoses, a cracked hydraulic cylinder, or low hydraulic fluid levels.
  
• Troubleshooting: Start by inspecting the hydraulic system for any visible leaks. Check the hoses, cylinders, and connections to ensure there is no fluid escaping. If the fluid level is low, top it up with the correct type of hydraulic fluid as specified by the manufacturer. If you find any leaks, replace the damaged components before attempting to operate the machine again.
  

1. Faulty Blade Cylinder or Seal
   

The blade of the John Deere 135C is raised and lowered using a hydraulic cylinder. Over time, seals within the cylinder can wear out or fail, leading to a loss of pressure and preventing the blade from staying up.

• Symptoms: The blade fails to hold its position or drifts downward after being raised.
  
• Possible Causes: Worn seals, damaged piston, or a faulty cylinder.
  
• Troubleshooting: Inspect the hydraulic cylinder for any visible signs of damage or oil leakage. If you notice fluid leaking from the cylinder, it could indicate a problem with the seals. In this case, you may need to rebuild or replace the hydraulic cylinder. Replacing the seals in the cylinder can often resolve the issue without needing to replace the entire component.
  

1. Faulty Blade Control Valve
   

The blade control valve regulates the flow of hydraulic fluid to the blade's lift cylinder. If the valve becomes clogged or damaged, it can cause the blade to malfunction by not maintaining the required pressure.

• Symptoms: The blade is unresponsive to control inputs or does not hold its position.
  
• Possible Causes: A clogged or malfunctioning control valve, or debris in the hydraulic system.
  
• Troubleshooting: Start by cleaning the valve and inspecting it for any visible signs of damage. A clogged valve can usually be cleaned with a suitable solvent, but if there’s significant damage to the valve, it may need to be replaced. Check the entire hydraulic system for any signs of contamination, which could cause blockages in the valve and other components.
  

1. Electrical or Sensor Malfunctions
   

Modern machinery, like the John Deere 135C, often relies on sensors and electrical systems to monitor and control hydraulic operations. If there’s an issue with the electrical system, it can affect the operation of the blade.

• Symptoms: The blade may fail to raise or lower, or the operator may see warning lights on the dashboard.
  
• Possible Causes: A malfunctioning sensor, faulty wiring, or an electrical component failure.
  
• Troubleshooting: Inspect the electrical system for any broken wires or loose connections. Check the blade position sensors for proper operation and ensure they are correctly calibrated. If any electrical components appear faulty, they may need to be replaced or repaired.
  

1. Improper Blade Adjustment
   

In some cases, the issue may not lie with the hydraulic or electrical systems but rather with the mechanical components of the blade itself. If the blade is not properly adjusted, it may not hold its position when raised.

• Symptoms: The blade drifts downwards or is difficult to control during operation.
  
• Possible Causes: Misalignment of the blade, worn pins or bushings, or improper tension in the blade mounting system.
  
• Troubleshooting: Inspect the blade and its mounting system for any signs of wear or misalignment. Ensure that the pins, bushings, and other mechanical components are in good condition and properly adjusted. If you find any worn parts, replace them as necessary.
  

Preventive Maintenance for the John Deere 135C Blade
To avoid future issues with the blade on the John Deere 135C, it’s essential to maintain the machine properly. Here are a few preventive maintenance tips to keep your blade in working order:

1. Regular Hydraulic Fluid Checks
   Keep an eye on the hydraulic fluid levels and quality. Ensure the fluid is clean and free of contaminants. Regularly change the hydraulic fluid to keep the system running smoothly.
   
2. Inspect Hydraulic Hoses and Cylinders
   Inspect hydraulic hoses and cylinders frequently for leaks or damage. Replace any damaged parts promptly to avoid fluid loss and prevent bigger problems down the road.
   
3. Clean and Calibrate Sensors
   The sensors in your John Deere 135C play an important role in controlling the blade. Ensure they are clean and properly calibrated to prevent malfunctions.
   
4. Lubricate the Blade Mounting System
   Keep the blade mounting system well-lubricated to prevent wear on pins and bushings. Regular lubrication helps to maintain smooth operation and extends the life of mechanical components.
   
5. Check for Debris or Obstructions
   After each use, ensure the blade and surrounding components are free of dirt and debris. Blockages can cause the blade to operate inefficiently, and leaving them unchecked can lead to long-term damage.
   

Real-World Example: Addressing Blade Failure in the Field
A construction company in Ohio faced a similar problem with their John Deere 135C when the blade kept drifting downward during operation. After inspecting the hydraulic lines and cylinders, they discovered a slow leak in the lift cylinder, which caused a gradual loss of hydraulic pressure. Replacing the seals and recharging the system with fresh hydraulic fluid solved the problem, restoring the machine to full functionality.
Conclusion: Keeping the Blade of the John Deere 135C in Peak Condition
A blade that won’t stay up is a frustrating issue for any operator, but with the right troubleshooting steps, most problems can be resolved quickly. Whether the issue lies with the hydraulic system, the control valve, or electrical malfunctions, understanding the root causes of blade failure is essential for efficient repairs.
By following the tips provided in this guide and maintaining the machine regularly, you can extend the life of your John Deere 135C and keep it performing at its best. Regular inspections and preventive maintenance will save you time, money, and downtime on the job site, ensuring that the John Deere 135C continues to be a reliable and effective piece of equipment for years to come.