Volvo L220E Wheel Loader Front Tire Lift Issue

[MikePhua]

Overview
The Volvo L220E is a powerful wheel loader featuring advanced hydraulic and mechanical systems designed for heavy material handling and loading applications. A reported issue on some machines is the inability to lift the front tires off the ground during bucket raising or certain lifting operations. Understanding this problem requires insight into the loader’s load transfer dynamics, hydraulic pressures, and machine geometry.
Load Transfer and Tire Lift Mechanism

• When the loader’s bucket is raised with a heavy load, the machine’s weight distribution changes, shifting load from rear tires to the front.
  
• Ideally, under certain conditions, the rear tires should bear more weight, sometimes lifting the front tires slightly to improve traction and digging force.
  
• The L220E uses a load-sensing hydraulic system with variable displacement pumps that maximize efficiency by supplying flow based on hydraulic demand.
  
• The loader arms (lift cylinders) and linkage geometry determine the mechanical advantage and the extent of weight transfer during load lifting.
  

Possible Causes for Front Tires Not Lifting

• Insufficient Hydraulic Flow or Pressure: If lift cylinders lack pressure or oil flow due to pump wear, leaks, or valve faults, lifting force is reduced.
  
• Incorrect Machine Setup: Hydraulic linkage or arm geometry changes during maintenance or component replacement may affect load transfer.
  
• Wear or Damage: Worn hydraulic cylinders, pins, or bushings in lift mechanisms lead to reduced extension force.
  
• Tire Pressure or Suspension Issues: Unequal tire inflation or suspension stiffness can reduce tire lift during operations.
  
• Load Parameters: Lifting light loads or unbalanced material may not generate sufficient rearward weight shift to lift front tires.
  

Technical Specifications Affecting Lifting

• The L220E’s lift cylinders have a bore size of roughly 190 mm with strokes over 768 mm, driven at pressures up to 24 MPa (3,480 psi).
  
• Hydraulic flow rates reach about 200 liters per minute depending on engine rpm and pump operation.
  
• Torque parallel linkage (TP linkage) helps maintain bucket angle through the lift range, influencing load characteristics.
  

Troubleshooting and Solutions

• Check Hydraulic Components: Test pressure and flow at lift cylinders, inspect for leaks, and evaluate pump condition.
  
• Assess Mechanical Linkage: Inspect pins and bushings for excessive wear or damage, replace as needed.
  
• Verify Tire Pressure and Suspension: Ensure tires meet manufacturer specifications, check steering and suspension for binding.
  
• Load Testing: Try lifting varying load weights to observe load transfer behaviors and system responses.
  
• Consult Diagnostics: Use onboard diagnostic tools to check for hydraulic faults or error codes.
  

Glossary

• Load-Sensing Hydraulics: Systems adjusting pump flow to meet demand, improving fuel economy.
  
• Torque Parallel Linkage: Linkage design that keeps bucket angle constant.
  
• Lift Cylinder: Hydraulic cylinders that raise and lower loader arms.
  
• Hydraulic Flow Rate: Oil volume delivered per unit time in the hydraulic system.
  
• Bore: Internal diameter of a cylinder influencing force generation.
  

Conclusion
The inability of a Volvo L220E to lift front tires off the ground points to hydraulic flow or pressure issues, mechanical wear, or incorrect operating parameters. Understanding the machine’s hydraulic demands and mechanical linkage function is key to diagnosing and resolving this problem. Routine maintenance and diagnostic testing help maintain optimal lifting performance and load transfer for efficient and safe operation on the jobsite.