Why Does the Tilt Drift on a Ford CL20 Skid Steer

[MikePhua]

The Ford CL20 and Its Hydraulic Simplicity
The Ford CL20 skid steer loader was introduced in the late 1970s as part of Ford’s compact equipment lineup. Designed for light-duty construction, landscaping, and agricultural tasks, the CL20 featured a straightforward mechanical layout with a small diesel engine and a basic open-center hydraulic system. Its compact footprint and affordability made it popular among small contractors and property owners. Though Ford eventually exited the compact equipment market, many CL20 units remain in use today due to their mechanical simplicity and ease of repair.
Understanding Tilt Drift in Hydraulic Systems
Tilt drift refers to the gradual movement of the loader’s bucket tilt function when the control lever is released. In a properly functioning system, the bucket should hold its position. Drift indicates internal leakage or valve failure, allowing hydraulic fluid to bypass seals and flow back into the tank or other circuits.
In the CL20, this issue is typically traced to the valve spool assembly, which controls the tilt cylinder. When seals inside the spool wear out or the spool itself becomes scored, fluid leaks internally, causing the bucket to slowly tilt forward or backward even when the control is in neutral.
Terminology Explained

• Valve Spool: A cylindrical component inside the control valve that directs hydraulic flow based on lever position.
  
• Open-Center System: A hydraulic design where fluid continuously circulates through the valve until a function is activated.
  
• Internal Leakage: Fluid bypassing seals or worn surfaces inside a valve or cylinder, leading to unintended movement.
  

Common Causes of Tilt Drift

• Worn spool seals Over time, rubber seals degrade due to heat, contamination, and age. This allows fluid to leak past the spool even when the lever is centered.
  
• Scored spool or bore Dirt or metal particles can scratch the spool or valve body, creating paths for fluid to bypass.
  
• Obsolete parts Many CL20 components are no longer manufactured, making rebuilds difficult without custom seals or donor valves.
  
• Cylinder bypass Though less common, worn piston seals in the tilt cylinder can also cause drift. This is diagnosed by isolating the valve and testing cylinder response.
  

Repair Strategy and Recommendations

• Disassemble the valve spool assembly Clean all components and inspect for scoring. Replace seals if available or fabricate replacements using compatible materials.
  
• Use hydraulic schematic diagrams These help identify flow paths and confirm whether the issue lies in the valve or cylinder.
  
• Test with a known-good valve Temporarily install a donor valve from a similar machine to confirm diagnosis.
  
• Flush the hydraulic system Contaminants accelerate wear. Use clean fluid and replace filters during repair.
  

A Story from the Field
In Tennessee, a property owner purchased a clean-running CL20 only to discover severe tilt drift. After inspecting the valve, he found the spool seals were hardened and cracked. Replacement parts were unavailable, so he sourced Viton O-rings from a hydraulic shop and rebuilt the valve manually. The drift stopped immediately, and the loader returned to full functionality. He later documented the process to help others facing similar issues.
Preventive Maintenance Tips

• Replace hydraulic fluid every 500 hours
  
• Inspect control valve seals annually
  
• Use magnetic plugs to detect metal wear
  
• Store the machine indoors to reduce seal degradation
  

Conclusion
Tilt drift in a Ford CL20 skid steer is almost always caused by internal leakage in the valve spool assembly. While parts may be obsolete, careful inspection, seal replacement, and system flushing can restore proper function. With a bit of ingenuity and mechanical skill, these vintage machines can continue serving reliably for years to come.