Replacing the Hydraulic Line from Pump to Filter on a Bobcat 751 Skid Steer

[MikePhua]

Introduction
The Bobcat 751 skid steer loader, introduced in the late 1980s, is a compact yet powerful machine renowned for its versatility and reliability. Over the years, it has become a staple in various industries, from construction to landscaping. However, like all machinery, it requires regular maintenance to ensure optimal performance. One critical component that often needs attention is the hydraulic system, particularly the hydraulic line running from the pump to the filter. This article provides a comprehensive guide on replacing this hydraulic line, addressing common challenges, and offering practical solutions.
Understanding the Hydraulic System
The hydraulic system in the Bobcat 751 is responsible for powering various functions, including lifting, tilting, and auxiliary operations. The hydraulic line from the pump to the filter plays a crucial role in maintaining the cleanliness and efficiency of the hydraulic fluid, which is vital for the system's performance. Over time, this line can become worn, leading to leaks or reduced efficiency.
Common Issues with the Hydraulic Line

1. Leaks and Contamination: The most prevalent issue is leakage, often caused by wear or damage to the hydraulic line. This can lead to contamination of the hydraulic fluid, compromising the system's performance.
   
2. Clogging: Debris or contaminants can accumulate in the hydraulic line, leading to blockages that restrict fluid flow and reduce system efficiency.
   
3. Wear and Tear: Continuous operation can cause the hydraulic line to degrade, leading to cracks or breaks that necessitate replacement.
   

Steps to Replace the Hydraulic Line

1. Preparation: Before beginning the replacement process, ensure the machine is on a level surface, and the engine is turned off. Engage the parking brake to prevent any unintended movement.
   
2. Accessing the Hydraulic Line: Depending on the specific model and configuration, you may need to remove certain components to access the hydraulic line. This could include the filter mounting block or other obstructing parts. Use appropriate tools to carefully remove these components without causing damage.
   
3. Disconnecting the Old Line: Using suitable wrenches or socket sets, disconnect the old hydraulic line from both the pump and the filter. Be prepared for residual hydraulic fluid to leak out; have a container ready to catch any spillage.
   
4. Installing the New Line: Position the new hydraulic line in place, ensuring it matches the routing of the old line to avoid interference with other components. Connect the new line to both the pump and the filter, tightening the fittings securely without over-torquing.
   
5. Reassembly: Reinstall any components that were removed to access the hydraulic line. Ensure all fasteners are tightened to the manufacturer's specifications.
   
6. Testing: Start the engine and operate the hydraulic functions to check for proper operation. Inspect the new hydraulic line for any signs of leaks or issues.
   

Challenges and Solutions

• Limited Access: In some configurations, access to the hydraulic line can be restricted. In such cases, removing the exhaust manifold, fan, or other components may be necessary to gain sufficient access. Always refer to the service manual for specific guidance.
  
• Stubborn Fittings: Corroded or tight fittings can be challenging to remove. Applying penetrating oil and allowing it to sit for a period can help loosen these fittings. Using a crow's foot wrench or a short socket can provide the necessary leverage in tight spaces.
  
• Hydraulic Fluid Spillage: To minimize spillage, have absorbent materials on hand to catch any leaks. Properly dispose of any used hydraulic fluid in accordance with local regulations.
  

Maintenance Tips

• Regular Inspections: Periodically check the hydraulic lines for signs of wear, leaks, or damage. Addressing issues early can prevent more significant problems down the line.
  
• Use Quality Components: Always use OEM (Original Equipment Manufacturer) parts or high-quality aftermarket components to ensure compatibility and reliability.
  
• Proper Fluid Maintenance: Regularly change the hydraulic fluid and filter to maintain system cleanliness and efficiency.
  

Conclusion
Replacing the hydraulic line from the pump to the filter on a Bobcat 751 skid steer is a manageable task with the right tools and knowledge. By following the outlined steps and addressing common challenges proactively, you can ensure the continued performance and longevity of your machine's hydraulic system. Regular maintenance and attention to detail are key to keeping your Bobcat 751 operating at its best.