Bobcat 337 Blade and House Inop: Troubleshooting and Solutions

[MikePhua]

The Bobcat 337 mini excavator, known for its compact design and powerful performance, is widely used in a variety of construction and excavation tasks. However, like any heavy machinery, it can experience issues that affect its efficiency. One common problem that operators face is the inoperative blade and house rotation, which can significantly limit the machine's versatility and productivity. This article delves into the potential causes of such issues, how to diagnose them, and the steps to take to resolve them.
Overview of the Bobcat 337 Mini Excavator
The Bobcat 337 is part of the company’s extensive lineup of mini excavators, designed to provide high performance in confined spaces. With a working weight of around 8,000 lbs, the 337 is well-suited for urban construction, landscaping, and small-scale demolition projects. Some of its key specifications include:

• Engine Power: 35.3 hp
  
• Operating Weight: 7,990 lbs
  
• Max Digging Depth: 12.5 feet
  
• Bucket Capacity: 0.25 cubic yards
  
• Max Reach at Ground Level: 18 feet
  

The 337 is known for its strong digging capabilities, and its compact size allows it to maneuver in tight spaces. The blade and house rotation, which are essential for stabilizing the machine and facilitating efficient excavation, are powered by hydraulic systems. When these components fail to operate, it can hinder the overall functionality of the excavator.
Understanding the Blade and House Mechanisms
The blade and house rotation mechanisms are integral parts of the Bobcat 337. They are powered by the hydraulic system, and their failure can be caused by several factors. Here's a breakdown of how each system works:

• Blade Mechanism: The blade, located at the front of the mini excavator, is used for stabilizing the machine and for minor grading tasks. It is lowered and raised hydraulically and is also used to push material during excavation.
  
• House Rotation: The house rotation system enables the upper structure (house) of the excavator to rotate, allowing the operator to swing the boom and bucket in different directions. This is a crucial function for digging and positioning.
  

The blade and house systems are controlled by hydraulic actuators, and when either system becomes inoperative, it can render the machine much less functional.
Common Causes of Blade and House Failure
Several issues could cause the blade and house rotation to stop working. Below are the most common causes, along with troubleshooting tips.
1. Low or Contaminated Hydraulic Fluid
Hydraulic systems rely on fluid to transmit power from the pump to the actuators. Low hydraulic fluid levels or contaminated fluid can lead to inadequate pressure, causing the blade and house to become inoperative.

• Symptoms: Sluggish or unresponsive blade and house movements, grinding noises, or complete failure of rotation.
  
• Solution: Check the hydraulic fluid level and ensure that it is within the recommended range. If the fluid is low, top it up with the proper hydraulic fluid. If the fluid appears dirty or contaminated, it should be replaced, and the hydraulic filter should be changed.
  

2. Faulty Hydraulic Pump
The hydraulic pump generates the pressure needed for the blade and house to operate. A malfunctioning or worn-out hydraulic pump may not be able to generate enough pressure, resulting in inoperative blade and house functions.

• Symptoms: The blade and house fail to operate despite sufficient fluid levels, or they respond very slowly.
  
• Solution: Test the hydraulic pump to check if it’s producing the required pressure. If the pump is faulty, it will need to be repaired or replaced.
  

3. Hydraulic Hose or Fitting Leaks
Hydraulic hoses and fittings are responsible for delivering pressurized fluid to various parts of the hydraulic system. Leaks in the hoses or fittings can lead to a loss of pressure, preventing the blade and house from functioning.

• Symptoms: Visible hydraulic fluid leakage around hoses, connectors, or fittings.
  
• Solution: Inspect all hydraulic hoses and fittings for leaks or wear. If any are damaged, they should be replaced. Be sure to tighten all connections and replace any O-rings or seals that may be causing the leaks.
  

4. Clogged Hydraulic Valves or Filters
Hydraulic valves control the flow of fluid to different parts of the system, while the filters keep the fluid clean. A clogged valve or filter can restrict fluid flow, leading to a loss of power to the blade and house.

• Symptoms: Jerky movements, failure to respond to control inputs, or slow blade/house movement.
  
• Solution: Inspect and clean or replace any clogged hydraulic valves and filters. A dirty filter can lead to fluid contamination and should be replaced as part of regular maintenance.
  

5. Electrical or Control System Issues
The Bobcat 337's blade and house mechanisms are also controlled by electronic components, such as sensors and relays. If these components malfunction, they can prevent the hydraulic system from receiving the proper signals to operate.

• Symptoms: The blade and house won’t respond to operator inputs or there are error codes on the control panel.
  
• Solution: Check the electrical system for faulty connections, blown fuses, or damaged wiring. Inspect the control relays and sensors. If needed, use a diagnostic tool to read error codes and troubleshoot further.
  

Steps to Troubleshoot the Blade and House Failure
To effectively diagnose and fix the issue of the inoperative blade and house, follow these steps:

1. Check Hydraulic Fluid Levels: Ensure that the fluid is clean and at the correct level. Refill or replace the fluid if necessary.
   
2. Inspect Hydraulic Hoses and Fittings: Look for visible signs of leaks or damage. Replace any faulty hoses or fittings.
   
3. Test the Hydraulic Pump: If the fluid is good and there are no leaks, test the hydraulic pump for proper pressure. If the pump is malfunctioning, it should be replaced.
   
4. Inspect Filters and Valves: Clean or replace clogged filters and check the hydraulic valves for blockages.
   
5. Examine Electrical Components: Check wiring, relays, and sensors to ensure proper function. Use a diagnostic tool to identify any electrical issues.
   

Preventative Maintenance Tips for the Bobcat 337
To avoid issues with the blade and house in the future, perform the following preventative maintenance tasks:

1. Regularly Check Hydraulic Fluid: Maintain the proper fluid level and change the fluid according to the manufacturer’s maintenance schedule. This will help keep the system running smoothly.
   
2. Inspect Hoses and Fittings: Regularly check for leaks or damage, especially after heavy use.
   
3. Replace Filters and Clean Valves: Keep the hydraulic filters clean and replace them as needed to ensure proper fluid flow.
   
4. Monitor the Pump: Keep an eye on the hydraulic pump and replace it if you notice any decrease in performance.
   
5. Electrical System Checks: Periodically inspect the electrical system to ensure that all sensors and relays are functioning properly.
   

Conclusion
The Bobcat 337 mini excavator is a powerful and versatile machine, but like any piece of heavy equipment, it can experience issues that affect its functionality. When the blade and house rotation stop working, it’s essential to diagnose the issue thoroughly to avoid unnecessary downtime. By following the troubleshooting steps outlined in this article and performing regular maintenance, you can ensure the continued efficiency of the Bobcat 337 and its hydraulic systems.