Bobcat 763 AHC Problems: Troubleshooting the Auxiliary Hydraulic Circuit

[MikePhua]

The Bobcat 763, a popular skid steer loader, is known for its versatility and reliability. However, like any piece of heavy equipment, it can encounter issues over time. One common problem reported by operators is with the Auxiliary Hydraulic Circuit (AHC), which can affect the performance of attachments that require hydraulic power. This article outlines the common issues with the AHC in the Bobcat 763 and offers troubleshooting advice.
Understanding the Auxiliary Hydraulic Circuit (AHC)
The AHC on the Bobcat 763 is designed to provide hydraulic power to attachments like augers, grapples, or hydraulic hammers. It’s powered by the machine’s hydraulic system and is activated by the operator through the control panel. When functioning correctly, the AHC provides consistent flow to the attachments, allowing them to perform effectively.
Common AHC Problems in the Bobcat 763

1. No Hydraulic Power to Attachments
   One of the most common issues is when the auxiliary hydraulics fail to provide power to the attachments. This can prevent the machine from operating effectively, especially when using hydraulic-driven tools.
   • Possible Causes:
     • Blocked or clogged hydraulic lines.
       
     • Low hydraulic fluid levels.
       
     • Faulty hydraulic pump.
       
     • Problems with the AHC control valve.
       
   • Troubleshooting Tips:
     • Check the hydraulic fluid level and top it off if necessary.
       
     • Inspect the hydraulic lines for any blockages or leaks.
       
     • Test the hydraulic pump to ensure it is providing the correct pressure and flow.
       
     • Examine the AHC control valve for any malfunctions or stuck positions.
       
2. Intermittent Hydraulic Power
   Sometimes, the hydraulic power to the attachments may work intermittently, which can be frustrating and cause delays in work.
   • Possible Causes:
     • Air in the hydraulic system.
       
     • Dirty or clogged filters.
       
     • Faulty solenoid or control valve.
       
     • Leaks in the hydraulic lines or fittings.
       
   • Troubleshooting Tips:
     • Bleed the hydraulic system to remove any trapped air.
       
     • Clean or replace the hydraulic filters.
       
     • Inspect the solenoid and control valve for signs of wear or malfunction.
       
     • Tighten any loose fittings and check for leaks.
       
3. Erratic Flow or Pressure to Attachments
   Another issue that may arise is inconsistent hydraulic flow or pressure to the attachment, which can cause poor performance or lack of control over the attachment.
   • Possible Causes:
     • Incorrectly set pressure relief valve.
       
     • Malfunctioning or worn-out hydraulic components.
       
     • Incorrect hydraulic fluid.
       
   • Troubleshooting Tips:
     • Check and adjust the pressure relief valve to ensure it’s set to the correct pressure for the attachment.
       
     • Inspect the hydraulic pump and valves for any wear or malfunction.
       
     • Make sure the correct hydraulic fluid is being used for the Bobcat 763’s hydraulic system.
       
4. Slow or Weak Response from Attachments
   If the response from the attachment is slow or weak, it could indicate that the auxiliary hydraulic system is not functioning optimally.
   • Possible Causes:
     • Low engine speed affecting hydraulic power.
       
     • Air contamination in the hydraulic system.
       
     • Internal leaks in the hydraulic components.
       
   • Troubleshooting Tips:
     • Increase the engine speed to ensure the hydraulic pump is providing enough power.
       
     • Bleed the hydraulic system to remove any air.
       
     • Inspect the hydraulic system for leaks and replace any damaged seals or components.
       

Preventive Maintenance for the Bobcat 763 AHC

1. Regularly Check Hydraulic Fluid Levels
   Ensure that the hydraulic fluid levels are maintained at the correct level. Low fluid can cause the hydraulic system to operate inefficiently, leading to performance issues.
   
2. Inspect and Replace Hydraulic Filters
   Dirty or clogged hydraulic filters can reduce the flow of hydraulic fluid and cause system failures. Regularly inspect the filters and replace them as needed to keep the system running smoothly.
   
3. Check for Hydraulic Leaks
   Leaks in the hydraulic system can cause a loss of pressure and performance. Regularly inspect hydraulic hoses, fittings, and seals for signs of wear or leaks and replace any damaged parts immediately.
   
4. Test the AHC Control Valve
   The AHC control valve should be inspected regularly to ensure it is operating properly. If it becomes stuck or malfunctions, it can prevent hydraulic fluid from flowing to the attachments.
   
5. Maintain Proper Engine Speed
   Ensure that the engine speed is set appropriately for hydraulic operations. Low engine speed can result in insufficient hydraulic power, leading to weak or slow performance.
   

Conclusion
The Bobcat 763 AHC is a powerful system that helps operate various attachments, but like any hydraulic system, it is prone to issues if not properly maintained. By understanding the common problems, such as no hydraulic power, intermittent issues, erratic flow, or slow responses, operators can troubleshoot and resolve these issues quickly. Regular preventive maintenance, including checking fluid levels, inspecting filters, and testing hydraulic components, will help extend the life of the AHC and ensure optimal performance.