Troubleshooting Bobcat 773: No Auxiliary Hydraulic Lines – Causes, Solutions, and Insights

[MikePhua]

Introduction: Understanding Auxiliary Hydraulics in Skid Steers
Auxiliary hydraulics are an essential feature in modern skid steers like the Bobcat 773, providing the operator with the ability to power attachments such as augers, buckets, grapples, and sweepers. These hydraulic lines are integral for performing more complex tasks that go beyond the capabilities of a standard bucket or loader.
However, encountering issues with auxiliary hydraulic lines, especially when they aren't working or completely absent, can be frustrating. Understanding the underlying causes and troubleshooting steps is key to restoring full functionality to the equipment.
The Bobcat 773 and Its Hydraulic System
The Bobcat 773, a popular model known for its versatility and performance, utilizes an auxiliary hydraulic system that allows the machine to support various attachments. This system is powered by the machine’s hydraulic pump, which delivers fluid to the auxiliary lines that run to the front of the loader. When there’s no sign of auxiliary hydraulic lines, it could indicate a problem with the system, the wiring, or a configuration issue.
Understanding the function of these auxiliary lines helps operators identify whether the issue lies within the hydraulic system itself or is related to another factor, such as incorrect setup or a failed component.
Common Causes of Missing or Non-Functional Auxiliary Hydraulics

1. Factory Configuration Error
   

One of the most common causes of a Bobcat 773 lacking auxiliary hydraulic lines is a factory configuration error. Some older Bobcat models, including early versions of the 773, were not equipped with these lines by default, depending on the model year and specific options selected. In such cases, the machine was delivered without auxiliary hydraulics, leaving the operator with no way to power attachments that require hydraulic fluid.
For operators purchasing second-hand equipment, it is crucial to verify whether the machine was equipped with auxiliary hydraulics. Sometimes, previous owners may have removed or neglected to maintain the system.

1. Disconnected or Disengaged Hydraulic Lines
   

If the machine is supposed to have auxiliary hydraulics, the next potential issue could be disconnected or disengaged hydraulic lines. Over time, hydraulic lines may become loose or disconnected due to wear and tear, or they might have been removed intentionally for other reasons, such as repairs or upgrades. This can lead to a situation where it appears that there are no auxiliary lines, even though they were originally present.

1. Faulty Hydraulic Valve or Pump
   

Another common culprit for non-functional auxiliary hydraulics is a faulty hydraulic valve or pump. The valve controls the flow of fluid to the auxiliary lines, and if it malfunctions, it can prevent hydraulic fluid from reaching the attachments. Similarly, issues with the hydraulic pump, such as a clogged filter or pump failure, can also result in a lack of pressure and, therefore, a non-functional auxiliary system.

1. Electrical System Failure
   

The Bobcat 773 uses an electrically controlled hydraulic system, and a failure in the wiring or electrical components can cause issues with the auxiliary hydraulics. Problems like blown fuses, faulty switches, or damaged wiring may prevent the hydraulic system from engaging correctly. In some cases, the auxiliary hydraulic lines might be intact, but the system is not receiving the necessary power to operate.
Steps to Troubleshoot and Fix the Issue

1. Inspect the Hydraulic Lines and Valves
   

Start by carefully inspecting the hydraulic lines to ensure that they are securely connected and not obstructed. Look for signs of wear, cracking, or leakage that could explain why the auxiliary hydraulics are not working. If the lines seem to be in good condition, check the valve that controls the flow of hydraulic fluid to the attachments. A stuck or malfunctioning valve could be preventing the hydraulic fluid from reaching the auxiliary lines.

1. Check the Hydraulic Pump
   

Inspect the hydraulic pump for any signs of damage or wear. The pump is responsible for generating pressure to power the hydraulic attachments. If the pump is not producing enough pressure, the auxiliary lines will not function properly. If the fluid levels are low, this could also contribute to poor performance. If necessary, replace the pump or clean the filters to restore optimal performance.

1. Examine the Electrical System
   

Next, inspect the electrical system that controls the auxiliary hydraulics. This includes checking the fuses, relays, switches, and wiring. If you suspect a faulty electrical component, replacing the fuse or relay is a good first step. For more complex issues, you may need to consult the wiring diagram and check for shorts or damaged wiring that may be preventing the system from engaging.

1. Consult the Operator’s Manual
   

If the Bobcat 773 was originally configured with auxiliary hydraulics, consult the operator's manual for troubleshooting tips and detailed diagrams of the hydraulic and electrical systems. Many operators may overlook the importance of the manual, but it contains valuable information specific to your model and can help guide you through the troubleshooting process.
Real-World Example: A Case of Missing Auxiliary Lines
A construction company operating in the Midwest once encountered a situation where their Bobcat 773 skid steer was unable to power an auger attachment. After further inspection, it was discovered that the machine, purchased second-hand, had been sold without the necessary auxiliary hydraulic lines—a configuration issue that had gone unnoticed during the purchase. The company had to source the correct hydraulic lines, install the required valves, and hook up the system. This led to additional costs and downtime, but they were eventually able to get the equipment back in working order.
In another instance, an operator working in a large-scale landscape project realized that their auxiliary hydraulics stopped working midway through a project. After inspecting the system, they found that the valve responsible for directing hydraulic fluid had malfunctioned. The part was replaced, and the auxiliary hydraulics were restored, allowing the operator to continue working without any further delays.
Preventive Measures and Maintenance Tips

1. Regular Hydraulic System Inspections
   

Regularly check the auxiliary hydraulic system for signs of leaks, wear, or any loss of pressure. This can prevent issues from escalating and ensure the system remains functional when needed.

1. Upgrade and Retrofit
   

If your Bobcat 773 was not originally equipped with auxiliary hydraulics, consider retrofitting it with a kit designed for your model. Several aftermarket companies offer retrofitting kits that allow operators to add auxiliary hydraulic functionality to older machines.

1. Hydraulic Fluid Maintenance
   

Ensure the hydraulic fluid is kept at proper levels and replace it according to the manufacturer’s recommendations. Low fluid levels can lead to system failures, and dirty fluid can damage components, leading to costly repairs.
Conclusion: Maximizing the Utility of Your Bobcat 773
When auxiliary hydraulics fail to work or are absent, it can significantly impact the versatility of your Bobcat 773 skid steer. However, by understanding the system, performing regular inspections, and following proper troubleshooting techniques, operators can restore full functionality to their machine. Whether the problem stems from a factory configuration, faulty components, or an electrical failure, timely attention and preventive maintenance will ensure that the Bobcat 773 continues to serve as a reliable tool on the job site.
By investing in the right equipment, performing regular checks, and staying informed about the machine’s capabilities, operators can get the most out of their Bobcat 773, turning it into a powerhouse capable of handling a variety of tasks with ease.