Replacing the Hydraulic Tank on the Bobcat T770 Skid Steer: A Complete Guide

[MikePhua]

Introduction to the Bobcat T770 Skid Steer
The Bobcat T770 is a versatile and powerful skid steer loader designed for heavy-duty work across a wide range of industries, including construction, landscaping, and material handling. With a rated operating capacity of over 2,600 pounds and advanced hydraulic systems, the T770 excels in tasks that require high power and maneuverability. It is equipped with a compact design, allowing operators to work in tight spaces while maintaining impressive lifting capabilities and speed.
One critical aspect of the T770's functionality is its hydraulic system, which powers its lift arms, bucket, and other attachments. The hydraulic tank plays a central role in this system by holding and circulating hydraulic fluid, ensuring that all hydraulic components operate smoothly and efficiently. Over time, wear and tear can lead to issues such as leaks or loss of pressure, making the replacement of the hydraulic tank necessary.
The Role of the Hydraulic Tank in the Bobcat T770
The hydraulic tank in the Bobcat T770 serves several essential functions within the hydraulic system:

1. Fluid Storage: The tank holds hydraulic fluid, which is critical for transmitting force to various components, such as the boom, bucket, and tracks.
   
2. Heat Dissipation: Hydraulic fluid can become very hot during operation. The tank helps to dissipate heat, ensuring that the fluid remains at a safe temperature and maintains its viscosity, which is vital for optimal hydraulic performance.
   
3. Filtration: The hydraulic tank is often connected to a filtration system that removes contaminants from the fluid before it is recirculated, preventing damage to the pump, valves, and other components.
   
4. Pressure Regulation: The tank works in tandem with other hydraulic system components to maintain pressure balance, which ensures that the machine operates efficiently and smoothly.
   

When the hydraulic tank malfunctions or begins to leak, it can lead to a variety of operational problems, including loss of hydraulic pressure, overheating, or contamination of the hydraulic fluid. In such cases, replacing the hydraulic tank is the best solution.
Signs That the Hydraulic Tank Needs Replacement
Several indicators suggest that the hydraulic tank on the Bobcat T770 may need to be replaced or repaired:

1. Fluid Leaks: One of the most obvious signs of a problem is visible hydraulic fluid leaks around the tank, fittings, or hoses. Leaks can occur due to cracks or damage to the tank or its seals.
   
2. Decreased Hydraulic Performance: If the T770's hydraulic system begins to perform poorly—such as reduced lift capacity, sluggish bucket movement, or unresponsive controls—it may be due to a loss of hydraulic fluid or pressure, which can be caused by a faulty tank.
   
3. Contaminated Fluid: If the hydraulic fluid appears dirty, cloudy, or milky, it may indicate that the tank is no longer effectively filtering contaminants from the fluid, or the seals are allowing dirt to enter the system.
   
4. Excessive Heating: The hydraulic system should not overheat during normal operation. If the tank is not able to dissipate heat effectively, the fluid may overheat, causing damage to the hydraulic components.
   
5. Visible Cracks or Damage to the Tank: Cracks, dents, or other visible damage to the hydraulic tank may indicate that it needs to be replaced, as damaged tanks can compromise the integrity of the hydraulic system.
   

Step-by-Step Guide to Replacing the Hydraulic Tank on the Bobcat T770
Replacing the hydraulic tank on the Bobcat T770 is a relatively straightforward task but requires careful attention to detail. Below is a comprehensive step-by-step guide to replacing the hydraulic tank:
1. Preparation and Safety

• Turn Off the Machine: Ensure that the machine is powered off, and the engine has cooled down completely before beginning any work.
  
• Disconnect the Battery: For safety reasons, disconnect the battery to prevent accidental electrical shorts during the procedure.
  
• Relieve Hydraulic Pressure: Before removing any hydraulic components, relieve the pressure in the hydraulic system by operating the hydraulic controls to extend and retract the arms and bucket, allowing any trapped pressure to be released.
  

2. Drain the Hydraulic Fluid

• Locate the Drain Plug: Find the drain plug on the hydraulic tank, typically located at the bottom of the tank.
  
• Position a Drain Pan: Place a suitable drain pan or container underneath the tank to catch the hydraulic fluid. Depending on the tank’s capacity, you may need a larger container to hold the fluid.
  
• Drain the Fluid: Remove the drain plug and allow the hydraulic fluid to fully drain out of the tank. Be cautious, as hydraulic fluid can be hot, especially if the machine was recently in use.
  

3. Remove the Hydraulic Lines and Hoses

• Disconnect Hydraulic Hoses: Using a wrench or appropriate tool, disconnect the hydraulic lines and hoses attached to the tank. Take care to note the orientation and placement of each hose, as they will need to be reattached to the new tank.
  
• Seal Open Ports: Once the hoses are disconnected, seal the open hydraulic ports to prevent contamination from entering the hydraulic system during the replacement process.
  

4. Remove the Old Hydraulic Tank

• Loosen the Tank Mounting Bolts: Identify the bolts or fasteners securing the hydraulic tank in place. Use a wrench or socket to loosen and remove these fasteners.
  
• Lift the Tank Out: Once the mounting bolts are removed, carefully lift the hydraulic tank out of the machine. Depending on the size and weight of the tank, you may need a hoist or lifting equipment to assist in removing it.
  

5. Install the New Hydraulic Tank

• Position the New Tank: Carefully place the new hydraulic tank in the mounting area. Ensure that it is aligned correctly with the mounting holes and that any necessary brackets or supports are in place.
  
• Secure the Tank: Reinstall the mounting bolts and fasten the tank securely. Ensure that the tank is tightly secured to prevent any movement during operation.
  

6. Reconnect the Hydraulic Lines and Hoses

• Reconnect the Hoses: Reattach the hydraulic hoses and lines to the new tank, following the original configuration. Tighten the connections to prevent leaks.
  
• Inspect for Leaks: Once the hoses are connected, double-check each connection to ensure they are properly tightened and secure.
  

7. Refill the Hydraulic Fluid

• Add New Hydraulic Fluid: Refill the hydraulic tank with the recommended type and amount of hydraulic fluid. Be sure to use clean, high-quality fluid to prevent contamination of the hydraulic system.
  
• Check Fluid Level: After filling the tank, check the fluid level on the dipstick or sight gauge to ensure it is within the proper range.
  

8. Test the Hydraulic System

• Start the Engine: Turn the machine’s engine back on and let it run for a few minutes.
  
• Operate the Hydraulic System: Test the hydraulic system by operating the loader arms, bucket, and any other hydraulic components. Check for smooth and responsive movement.
  
• Monitor for Leaks: Carefully inspect all hydraulic connections for leaks. If any leaks are detected, immediately tighten the connections.
  

Common Issues and Troubleshooting
While replacing the hydraulic tank on the Bobcat T770 is typically a straightforward process, several issues may arise:

1. Fluid Leaks: If you notice fluid leaking from the tank or hose connections after installation, double-check all connections for tightness. Leaks may also occur if the wrong type of hydraulic fluid was used.
   
2. Air in the System: If the hydraulic system is not responding as expected after replacement, there may be air trapped in the lines. To resolve this, cycle the hydraulic system by moving the loader arms and bucket several times to allow air to escape.
   
3. Inconsistent Hydraulic Pressure: If the machine shows signs of low hydraulic pressure, check the fluid level again and ensure the fluid is clean. Also, inspect the hydraulic pump and filter for any blockages or damage.
   

Real-World Example: Replacing the Hydraulic Tank on a Bobcat T770
A landscaping company in Texas was experiencing reduced hydraulic performance on their Bobcat T770. The loader's arms were sluggish, and the bucket wasn't responding as quickly as it should. Upon inspection, the team discovered that the hydraulic tank was cracked, causing a slow leak of fluid.
The team quickly drained the hydraulic fluid, removed the old tank, and replaced it with a new one. After refilling the system with fresh fluid, they tested the loader and were pleased to see that the hydraulic system was operating at full capacity again. The repair not only improved the machine’s performance but also extended its lifespan.
Conclusion
Replacing the hydraulic tank on the Bobcat T770 is a relatively straightforward but essential maintenance task. By following the proper procedures and using the correct tools, operators can ensure that the hydraulic system continues to function efficiently, preventing costly downtime and maintaining the loader's performance. Regular maintenance and quick response to hydraulic issues will keep the Bobcat T770 in top shape for years to come.