Hydraulic Troubleshooting and Maintenance for Bobcat 853 Skid Steer Loaders

[MikePhua]

The Bobcat 853 skid steer loader, a versatile machine introduced in the early 1990s, has become a staple in various industries due to its compact size and powerful hydraulics. However, as with any heavy equipment, operators may encounter hydraulic issues over time. This article delves into common hydraulic problems associated with the Bobcat 853 and provides insights into troubleshooting and maintenance practices to ensure optimal performance.

Understanding the Hydraulic System of the Bobcat 853
The hydraulic system in the Bobcat 853 is integral to its operation, powering functions such as lifting, tilting, and driving. The system comprises several key components:

• Hydraulic Pump: Supplies pressurized fluid to the system.
  
• Hydraulic Cylinders: Facilitate movement of the lift arms and tilt functions.
  
• Control Valves: Direct the flow of hydraulic fluid to various components.
  
• Filters and Suction Screens: Prevent contaminants from entering the system.
  

Regular maintenance of these components is crucial to prevent performance degradation.

Common Hydraulic Issues and Troubleshooting

1. Slow or Weak Lift and Tilt Functions
   • Symptoms: The lift arms or bucket tilt slowly or lack power, especially under load.
     
   • Potential Causes:
     • Contaminated or low hydraulic fluid levels.
       
     • Worn or damaged hydraulic cylinders.
       
     • Faulty control valves or relief valves.
       
   • Recommended Actions:
     • Inspect and replace hydraulic fluid and filters as needed.
       
     • Check for leaks around cylinders and hoses.
       
     • Test and clean or replace control and relief valves.
       
2. Intermittent Hydraulic Power Loss
   • Symptoms: Sudden loss of hydraulic power during operation.
     
   • Potential Causes:
     • Clogged suction screen or filters.
       
     • Air trapped in the hydraulic system.
       
     • Faulty charge pump or main hydraulic pump.
       
   • Recommended Actions:
     • Clean or replace the suction screen and filters.
       
     • Bleed air from the hydraulic system.
       
     • Test the charge and main pumps for proper operation.
       
3. Hydraulic Fluid Overheating
   • Symptoms: Hydraulic fluid temperature exceeds normal operating range.
     
   • Potential Causes:
     • Overworked hydraulic system.
       
     • Insufficient fluid levels or degraded fluid.
       
     • Blocked or malfunctioning hydraulic cooler.
       
   • Recommended Actions:
     • Reduce load and operating time to prevent overheating.
       
     • Ensure proper fluid levels and replace degraded fluid.
       
     • Inspect and clean the hydraulic cooler.
       

Maintenance Practices to Prevent Hydraulic Issues

• Regular Fluid Checks: Monitor hydraulic fluid levels and quality. Replace fluid at intervals recommended by the manufacturer.
  
• Filter Maintenance: Replace hydraulic filters at regular intervals to prevent contamination.
  
• Component Inspections: Regularly inspect hydraulic cylinders, hoses, and valves for signs of wear or damage.
  
• System Bleeding: Periodically bleed the hydraulic system to remove air and ensure efficient operation.
  

Case Study: Resolving Hydraulic Power Loss in a Bobcat 853
A Bobcat 853 owner reported intermittent hydraulic power loss during operation. Upon inspection, it was discovered that the suction screen was clogged with debris, restricting fluid flow. After cleaning the screen and replacing the filters, hydraulic performance was restored, demonstrating the importance of regular maintenance.

Conclusion
The Bobcat 853 is a reliable machine when its hydraulic system is properly maintained. By understanding common hydraulic issues and implementing proactive maintenance practices, operators can ensure the longevity and efficiency of their equipment. Regular inspections, timely repairs, and adherence to maintenance schedules are key to preventing hydraulic problems and maximizing machine performance.