Bobcat 751 Lift Issues

[MikePhua]

A user reported lift issues with the Bobcat 751 skid steer. The lifting function seems unstable and does not operate properly, resulting in work disruptions. The issue may stem from faults in the hydraulic system, control system, or mechanical components.
Common Causes

1. Low or Contaminated Hydraulic Oil
   The hydraulic system’s performance depends on hydraulic oil. If the oil level is low or the oil is contaminated, the hydraulic system may fail to operate correctly, leading to lifting issues.
   
2. Hydraulic Pump Failure
   The hydraulic pump is the core component of the hydraulic system. If the pump is damaged or malfunctioning, it may lead to poor lifting performance.
   
3. Control Valve Issues
   The control valve regulates the flow of hydraulic oil to various actuators. If the control valve fails, it can lead to uneven hydraulic flow distribution, affecting the lift function.
   
4. Electrical System Failures
   The Bobcat 751 lift control system could be impacted by electrical issues, such as relay failures, sensor problems, or loose wiring. Any failure in the electrical components could cause the lift function to fail.
   
5. Hydraulic Hose Leaks
   Leaks in the hydraulic hoses or connections could cause hydraulic oil loss, which would lower the system’s pressure, affecting the machine’s lift capacity.
   
6. Mechanical Component Damage
   Mechanical parts such as lift arms, hooks, or supports could be damaged, leading to reduced lifting ability. If these parts are damaged or worn out, they may need repair or replacement.
   

Troubleshooting Steps

1. Check Hydraulic Oil
   Check the oil level and quality. Ensure the oil level is within the normal range and the oil is clean. If the oil is contaminated or the level is low, top up or replace the hydraulic oil.
   
2. Test Hydraulic Pump
   Use a pressure gauge to test the output pressure of the hydraulic pump. If the pressure is low, the pump may be faulty and require repair or replacement.
   
3. Inspect Control Valve
   Check the operation of the hydraulic control valve. This can be done manually or using diagnostic tools to verify smooth operation. If the valve is faulty, it may need repair or replacement.
   
4. Inspect Electrical System
   Check the electrical system components, including the battery, wiring, relays, and sensors. Ensure that all circuits are properly connected and there are no loose or damaged parts. Use a multimeter to check voltage and current if needed.
   
5. Inspect Hydraulic Hoses
   Check the hydraulic hoses and connections for leaks. Wipe the hoses with a cloth or paper towel to see if any oil is leaking. If a leak is found, replace or repair the damaged hoses.
   
6. Inspect Mechanical Components
   Check the mechanical parts such as lift arms, connectors, and hooks. Look for any loose or damaged components. Damaged parts should be replaced.
   

Solutions

• Replace or Top Up Hydraulic Oil: If the oil is low or contaminated, replace or top up the hydraulic oil.
  
• Repair or Replace Hydraulic Pump: If the pump is faulty, repair or replace it.
  
• Repair or Replace Control Valve: Check the control valve, and if it’s faulty, repair or replace it.
  
• Fix Electrical System Problems: Inspect and repair any issues with the electrical system, including the battery, wires, and relays.
  
• Repair Hydraulic Hose Leaks: Replace any damaged hoses or fittings that are leaking hydraulic fluid.
  
• Replace Damaged Mechanical Components: If any mechanical parts are damaged, replace them to restore lifting capability.
  

Conclusion
The lift issues with the Bobcat 751 skid steer are typically related to failures in the hydraulic system, electrical components, or mechanical parts. By systematically checking the hydraulic oil, pump, control valve, electrical system, hydraulic hoses, and mechanical parts, you can diagnose and resolve the issue quickly. Regular maintenance and inspections of these systems will help keep the machine running smoothly and prevent similar issues from occurring.