Bleeding the Hydraulic System on a 2016 Bobcat E26: A Detailed Guide

[MikePhua]

Hydraulic systems are critical to the operation of compact excavators like the 2016 Bobcat E26. When air enters the system, it can cause erratic operation, loss of power, or noise, making bleeding the hydraulic system an essential maintenance task. This guide explains the bleeding process, technical terms, causes of hydraulic air ingress, and troubleshooting tips.
Understanding the Hydraulic System

• Hydraulic Fluid: The medium transmitting power through hoses and cylinders. It must remain free of air and contaminants for efficient operation.
  
• Hydraulic Pump: Pressurizes fluid to drive actuators like boom cylinders and swing motors.
  
• Hydraulic Cylinders: Convert fluid pressure into mechanical force for movement.
  
• Bleed Valve / Nipple: A small valve allowing trapped air to escape from the hydraulic lines.
  
• Reservoir: Stores hydraulic fluid and allows air bubbles to settle out.
  

Common Causes of Air in Hydraulic Systems

• Leaking or loose hydraulic fittings and hoses.
  
• Low hydraulic fluid level, causing suction of air.
  
• Faulty or worn seals allowing air ingress.
  
• Improper bleeding after maintenance or hose replacement.
  

Step-by-Step Bleeding Procedure

• Step 1: Safety Preparation
  • Park the machine on level ground and shut off the engine.
    
  • Wear gloves and eye protection.
    
• Step 2: Check Fluid Levels
  • Inspect the hydraulic fluid reservoir and top up if needed using manufacturer-specified fluid.
    
• Step 3: Locate Bleed Points
  • Identify bleed valves on cylinders, control valves, or pump outlets.
    
• Step 4: Open Bleed Valves
  • Using appropriate tools, open bleed valves slightly to allow trapped air to escape.
    
• Step 5: Operate Controls Slowly
  • Start the engine and gently move the boom, arm, and bucket to pump out air bubbles.
    
  • Keep an eye on fluid levels and top up as necessary.
    
• Step 6: Close Bleed Valves
  • Once no more air bubbles emerge, securely close the valves.
    
• Step 7: Test System Operation
  • Check for smooth, consistent hydraulic movement without noise or hesitation.
    

Additional Tips and Troubleshooting

• Always use clean hydraulic fluid to avoid contamination.
  
• Inspect all hydraulic hoses and fittings for leaks or damage before bleeding.
  
• If air persists, consider checking for internal pump damage or worn seals.
  
• Avoid overfilling the reservoir, which can cause foaming.
  
• Perform bleeding slowly and systematically to prevent introducing new air.
  

Case Example
An operator of a 2016 Bobcat E26 experienced jerky boom movements and a loud noise from the hydraulic pump. After inspecting fluid levels and tightening several loose fittings, the operator performed a careful bleeding process using the cylinder bleed nipples. The result was smooth, quiet operation and restored power, preventing the need for costly repairs.
Maintenance Recommendations

• Regularly monitor hydraulic fluid levels and quality.
  
• Schedule periodic inspection of hoses and fittings for early leak detection.
  
• After any hydraulic component replacement, always bleed the system thoroughly.
  
• Maintain clean working conditions to minimize contamination risk.
  

Summary
Bleeding the hydraulic system on the Bobcat E26 is essential for maintaining precise and reliable operation. Air trapped in the system causes poor performance and potential damage. Following a step-by-step bleeding process, combined with thorough inspections and fluid management, ensures optimal hydraulic function. Proper maintenance prevents future issues and extends machine life.