773G Skid Steer Loader Auxiliary Hydraulics Not Working

[MikePhua]

1. Issue Overview
On the Panswork forum, a user reported that the auxiliary hydraulics on their CAT 773G skid steer loader were not functioning properly. The auxiliary hydraulic system is used to power various attachments, such as buckets or augers, by providing additional hydraulic support. When this system fails, it can affect the machine's performance, making it impossible to operate certain attachments.
2. How the Auxiliary Hydraulics Work
The auxiliary hydraulic system is designed to provide additional hydraulic power to attachments. Users can adjust the flow and pressure of the hydraulic fluid using control levers or buttons, depending on the task.

1. Hydraulic Pump: The hydraulic pump is the source of power for the auxiliary hydraulic system. It pushes hydraulic fluid through the system to various components to operate attachments. If the pump fails, the system will not be able to provide the necessary hydraulic support.
   
2. Control Valve: The control valve regulates the flow and direction of hydraulic fluid. Operators control the valve using the joystick or control panel, adjusting the system's performance. If the valve malfunctions, it may prevent hydraulic fluid from flowing properly, causing issues with attachment performance.
   
3. Hydraulic Lines: Hydraulic lines transport hydraulic fluid to various components. If the lines are blocked or damaged, the hydraulic system may not function as intended.
   

3. Common Causes and Troubleshooting Methods

1. Hydraulic Pump Failure:
   • If the hydraulic pump is not delivering sufficient fluid, the pump’s internal components may be damaged, or the hydraulic fluid level may be low.
     
   • Solution: Check the hydraulic fluid level and quality. If the pump is faulty, it may need to be replaced.
     
2. Control Valve Problems:
   • If the pump is functioning properly but the flow is still inadequate, the issue may lie in the control valve. Valve seals, worn valve spools, or sticking valves can prevent proper fluid flow.
     
   • Solution: Inspect the control valve to ensure the valve spool moves freely. Clean or replace any damaged components.
     
3. Blocked or Leaking Hydraulic Lines:
   • Blockages or leaks in the hydraulic lines can restrict fluid flow, preventing the auxiliary hydraulics from working.
     
   • Solution: Check all hydraulic lines for leaks or blockages. Clean the lines or replace damaged sections.
     
4. Electrical Issues:
   • Many modern skid steer loaders use electronic control systems to manage hydraulic functions. If there is an electrical fault, the hydraulic system may fail to engage.
     
   • Solution: Check the electrical connections, wiring, and control modules to ensure there are no loose connections or faults in the system.
     

4. Conclusion and Recommendations
When the auxiliary hydraulics on a CAT 773G skid steer loader are not working, it is typically caused by issues with the hydraulic pump, control valve, hydraulic lines, or electrical systems. Operators can troubleshoot by checking each component and addressing the specific cause of the failure.
Regular maintenance of the hydraulic system, including checking fluid levels, inspecting hydraulic lines, and ensuring the control valve is in good working condition, can help prevent these issues. If the problem persists, it is advisable to seek professional assistance to perform more in-depth repairs.