Troubleshooting T250 Lift Arms Slowly Drifting Up When in Float Mode

[MikePhua]

If you’re operating a Bobcat T250 and notice that the lift arms slowly drift upward when in float mode, it’s a common issue that can be caused by a few different factors. Understanding the root cause of this problem will allow you to address it effectively and prevent unnecessary wear on your equipment. Below is a breakdown of the issue and the possible solutions.
Understanding Float Mode
Float mode on a skid steer like the Bobcat T250 allows the lift arms to move freely with minimal resistance. This feature is designed to let the loader bucket or attachment follow the contour of the ground without exerting pressure on it, which is useful for tasks like grading or leveling. When in float mode, the lift arms should stay in place and not rise unless there is an issue with the hydraulic system.
What Causes Lift Arms to Drift Up in Float Mode?
If your T250’s lift arms are slowly drifting upward when in float mode, this is typically due to an issue with the hydraulic system, more specifically the following possible causes:

1. Hydraulic Cylinder Seals:
   • Cause: One of the most common reasons for lift arms drifting upward is a failure in the seals within the hydraulic cylinders. Over time, seals can wear out or become damaged, leading to hydraulic fluid bypassing the piston inside the cylinder, causing the lift arms to rise slowly.
     
   • Solution: Inspect the hydraulic cylinders for any visible signs of leakage or damage. If the seals are worn or leaking, they will need to be replaced. In some cases, you may need to completely rebuild the hydraulic cylinders.
     
2. Float Mode Valve Issue:
   • Cause: Another potential cause is a malfunction in the float mode valve. If the valve is not fully engaging or is stuck, it may fail to properly lock the hydraulic system in place, allowing fluid to pass through and causing the arms to drift.
     
   • Solution: Check the float mode valve for any issues such as dirt, wear, or damage. If the valve is malfunctioning, it may need to be cleaned or replaced to restore proper function.
     
3. Hydraulic Pressure Loss:
   • Cause: Low hydraulic pressure could also be to blame. If the system is not maintaining proper pressure, the lift arms may not stay in place and could drift upwards. This could be caused by a faulty hydraulic pump, a leaking hose, or a problem with the hydraulic fluid itself.
     
   • Solution: Inspect the hydraulic system for leaks, especially around hoses, fittings, and the pump. Ensure that the hydraulic fluid is at the correct level and is in good condition. If the pump or any components are faulty, they will need to be replaced.
     
4. Faulty Control Valve or Joystick:
   • Cause: The issue could also be linked to the control valve or joystick. If the joystick is malfunctioning or if the control valve is not properly controlling the flow of hydraulic fluid, it could cause unintended movement in float mode.
     
   • Solution: Check the joystick and control valve for any signs of wear or malfunction. If the valve is sticking or if the joystick is not returning to its neutral position, this could cause the issue. Cleaning or replacing the valve or joystick may resolve the problem.
     

Steps to Diagnose the Issue
If you’re unsure of the cause, follow these diagnostic steps to help pinpoint the issue:

1. Inspect the Hydraulic Cylinders: Check for any visible fluid leaks, especially around the piston seals. If there are signs of leakage, you will likely need to replace the seals or have the cylinders rebuilt.
   
2. Check Hydraulic Fluid Levels: Ensure the hydraulic fluid is at the correct level and is not contaminated. Low or dirty fluid can cause improper hydraulic function, including issues with lift arm movement.
   
3. Test the Float Mode Valve: Engage the float mode and observe if the valve fully engages and holds the lift arms in place. If the valve is sticking or not engaging correctly, it may need cleaning or replacement.
   
4. Monitor for Pressure Loss: Use a hydraulic pressure gauge to check for adequate pressure in the system. If the pressure is low, inspect the pump, hoses, and fittings for leaks.
   
5. Test the Control Valve and Joystick: Move the joystick and check if it is returning to its neutral position properly. Ensure the control valve is not stuck or malfunctioning.
   

How to Fix the Problem
Once you’ve identified the cause of the drifting lift arms, you can proceed with repairs:

1. Replace Seals in Hydraulic Cylinders: If the issue is with the seals in the hydraulic cylinders, you will need to disassemble the cylinders, clean them thoroughly, and replace any worn or damaged seals. If the cylinder itself is damaged, you may need to replace it.
   
2. Clean or Replace the Float Mode Valve: If the float mode valve is malfunctioning, cleaning it might restore proper function. However, if the valve is severely worn or damaged, it may need to be replaced.
   
3. Fix Hydraulic Leaks: Tighten any loose connections, replace any damaged hoses, or fix the hydraulic pump if needed to restore proper pressure in the system.
   
4. Replace Control Valve or Joystick: If the control valve or joystick is not functioning properly, replacing the faulty component will resolve the issue. Be sure to use genuine replacement parts to ensure compatibility.
   

Preventive Measures
To prevent similar issues from occurring in the future, follow these preventive measures:

1. Regular Maintenance: Perform regular maintenance on the hydraulic system, including checking fluid levels, cleaning filters, and inspecting hoses and seals for wear.
   
2. Proper Operation: Always operate the machine according to the manufacturer’s guidelines. Avoid excessive force or rapid movements, especially when using float mode, as this can cause wear on the hydraulic system.
   
3. Store the Machine Properly: When not in use, store the machine in a dry, sheltered environment to prevent rust and damage to the hydraulic components.
   

Conclusion
If the lift arms on your Bobcat T250 are slowly drifting up when in float mode, it’s likely due to a hydraulic issue, such as worn seals, a malfunctioning float valve, or a problem with the hydraulic system’s pressure. Diagnosing the issue involves checking the hydraulic cylinders, fluid levels, float mode valve, and control components. Once the cause is identified, appropriate repairs, such as replacing seals, cleaning valves, or fixing leaks, should restore proper functionality to the machine. Regular maintenance and proper operation will help prevent similar issues in the future, ensuring the longevity of your equipment.