Bobcat T770 Hydraulic Double Flush: Maintenance and Troubleshooting

[MikePhua]

The Bobcat T770 is a high-performance skid-steer loader designed for tough jobs in a variety of industries, including construction, landscaping, and agriculture. One of the most crucial components of this powerful machine is its hydraulic system, which controls everything from lifting the arms and bucket to running attachments like augers and grapples. Maintaining the hydraulic system is vital to ensure the machine operates efficiently and safely.
One of the key maintenance procedures to keep the hydraulic system in top condition is the hydraulic double flush. This process is essential when the hydraulic fluid is contaminated, the system is underperforming, or after repairs are made to the hydraulic components. A hydraulic double flush helps remove contaminants, air, and old fluid from the system, ensuring that the hydraulic pump, valves, and cylinders work optimally. Below is a detailed guide on the significance of hydraulic flushing, common symptoms, procedures, and troubleshooting advice for Bobcat T770 operators.
The Importance of Hydraulic Flushes
The hydraulic system in any heavy equipment, including the Bobcat T770, relies on clean and properly filtered fluid to operate effectively. Over time, contaminants such as dirt, metal shavings, or degraded fluid can accumulate in the system, causing wear on internal components and reducing overall performance. A hydraulic flush is a necessary maintenance task to remove these contaminants and restore the hydraulic system to its optimal functioning state.
In the case of the Bobcat T770, a double flush is often recommended. This involves performing the flushing process twice to ensure that all contaminants are thoroughly removed and that the fluid is clean and free of any harmful particles.
Symptoms That Indicate the Need for a Hydraulic Flush
Hydraulic problems can cause performance issues and potentially lead to expensive repairs. Here are some common symptoms that indicate the need for a hydraulic flush on the Bobcat T770:

1. Slow Hydraulic Response: If the arms, bucket, or auxiliary attachments are moving slower than usual, this could be a sign of contaminated fluid or air in the hydraulic lines.
   
2. Erratic Operation: Unpredictable or jerky movements when using the loader’s hydraulic functions often point to problems with the fluid, such as air bubbles, moisture, or particles in the system.
   
3. Overheating: If the hydraulic system is overheating, it could be due to the buildup of contaminants, clogged filters, or degraded fluid. Overheating can lead to serious damage, so it’s essential to address the issue immediately.
   
4. Excessive Noise: A whiny or grinding noise from the hydraulic pump often signals cavitation, a condition where air enters the hydraulic system. Cavitation can occur due to dirty or low fluid levels and is usually resolved by flushing the system.
   
5. Low Pressure: Low hydraulic pressure can also be a sign of fluid contamination or worn-out components. If the pump cannot generate sufficient pressure due to blockages or air, the hydraulic system will not function as expected.
   

The Double Flush Procedure
Performing a hydraulic double flush on the Bobcat T770 involves two distinct stages. Each stage is designed to cleanse the system thoroughly by removing contaminants and replenishing the system with fresh, clean hydraulic fluid. Here’s a general guide to performing the procedure:
1. Preparation
Before starting the double flush procedure, gather the necessary tools and materials, including:

• Replacement hydraulic fluid (check manufacturer specifications for the correct type and amount)
  
• Hydraulic fluid filter replacement (if necessary)
  
• Wrenches and other tools for removing drain plugs
  
• A container to catch the old fluid
  

2. First Flush
The first flush is designed to remove as much contaminated fluid as possible from the system.

• Drain the Old Fluid: Begin by draining the hydraulic fluid from the system. Be sure to drain from both the hydraulic reservoir and any other hydraulic lines where fluid may have collected.
  
• Replace Filters: If the filters have not been replaced recently, it is a good idea to replace them at this stage to prevent any remaining contaminants from circulating in the system.
  
• Flush the System: Refill the system with fresh hydraulic fluid and start the engine. Operate the loader’s hydraulic functions, such as the bucket and arms, to circulate the fluid throughout the system and flush out any debris or contaminants.
  
• Drain Again: After operating the hydraulic system for several minutes, drain the fluid again to remove any remaining contaminants.
  

3. Second Flush
The second flush ensures that any remaining contaminants are completely flushed out and that the system is thoroughly cleaned.

• Fill the System with Clean Fluid: Refill the system with new, clean hydraulic fluid. Make sure the fluid level is correct according to the manufacturer’s recommendations.
  
• Operate the Loader: Start the engine again and operate the loader’s hydraulics to circulate the clean fluid through the system. This step helps flush any remaining debris out of the system.
  
• Check the Fluid Level: After operating the system, check the fluid level once again. Add more fluid if necessary to ensure the system is properly filled.
  

4. Final Check
Once the double flush is complete, check the hydraulic performance. Look for any signs of improvement in the hydraulic response and ensure that no unusual noises, erratic movements, or overheating occurs. If the system is running smoothly, then the flush has been successful.
Tips for Maintaining the Hydraulic System
While the hydraulic double flush is an important maintenance procedure, regular maintenance and proper care will extend the life of your Bobcat T770’s hydraulic system. Here are some tips for maintaining optimal hydraulic performance:

1. Use High-Quality Fluid: Always use the hydraulic fluid recommended by the manufacturer. Low-quality fluids or incorrect types can cause issues with the pump, valves, and other components.
   
2. Change Filters Regularly: The hydraulic filters play a vital role in trapping contaminants and keeping the fluid clean. Regularly change the filters as part of routine maintenance.
   
3. Check Fluid Levels Frequently: Low fluid levels can lead to cavitation and pump damage. Always check the fluid level and top it up when necessary.
   
4. Inspect for Leaks: Leaks in the hydraulic lines or around the pump can result in a loss of fluid and system pressure. Regularly inspect the hydraulic lines and components for signs of leaks.
   
5. Avoid Overheating: If the hydraulic system is running too hot, shut the machine down and allow it to cool. Overheating can cause significant damage to the system and other engine components.
   

Conclusion
Performing a hydraulic double flush on the Bobcat T770 is an essential procedure to maintain the health of the machine’s hydraulic system. It helps remove contaminants, air, and moisture that can cause slow performance, overheating, and potential damage. By regularly flushing the system, replacing filters, and using high-quality fluids, operators can ensure that their Bobcat T770 continues to perform at its best for years to come.
Hydraulic system maintenance is an ongoing process that ensures the longevity and reliability of your equipment. Understanding the importance of regular maintenance and troubleshooting will help you keep your Bobcat T770 in peak condition and minimize downtime.