Bobcat 753 Front Auxiliary Hydraulic Switch: Troubleshooting and Solutions

[MikePhua]

The Bobcat 753 is a compact skid steer loader that has gained significant popularity due to its versatility, performance, and ease of use. It's often used in a variety of industries, from construction to landscaping, owing to its ability to work in tight spaces and its powerful hydraulic system. One of the key features of the Bobcat 753 is the front auxiliary hydraulic system, which allows the operator to power a variety of attachments such as augers, trenchers, or grapples. However, like any complex machinery, issues with the auxiliary hydraulic switch can arise, especially in older models. This article will explore common issues with the Bobcat 753’s front auxiliary hydraulic switch, provide solutions, and offer tips for maintaining optimal performance.
Understanding the Front Auxiliary Hydraulic System
Before diving into the troubleshooting and solutions, it's important to understand how the front auxiliary hydraulic system on the Bobcat 753 works. The front auxiliary hydraulics are powered by the skid steer’s main hydraulic system, which directs fluid to the front attachment for operations such as lifting, digging, and pushing. The hydraulic switch that controls this system is typically located on the operator's joystick, allowing the operator to easily activate or deactivate the auxiliary hydraulics as needed.
The auxiliary system is essential for using powered attachments, which makes the hydraulic switch an important part of the machine’s operation. If there’s an issue with the switch or the hydraulic system itself, it can significantly hinder the loader’s functionality and productivity.
Common Issues with the Front Auxiliary Hydraulic Switch
When dealing with a malfunctioning front auxiliary hydraulic switch, several issues might be at play. Understanding these problems can help narrow down the root cause and determine the appropriate solution.

1. Non-Functioning Hydraulic System
   • Symptoms: If the front auxiliary hydraulics are not working at all, the first thing to check is the hydraulic switch itself. Sometimes, the issue may stem from a worn-out or broken switch.
     
   • Possible Causes:
     • Worn-out or broken electrical connections within the switch.
       
     • A faulty switch that fails to complete the circuit, preventing hydraulic fluid from being directed to the front.
       
     • An electrical issue, such as a blown fuse or a short circuit, can disrupt the signal sent to the hydraulic solenoid.
       
2. Weak or Slow Hydraulics
   • Symptoms: If the front auxiliary hydraulics work intermittently or are weak, you may notice that the attachment doesn’t respond as quickly or as powerfully as expected.
     
   • Possible Causes:
     • Low hydraulic fluid levels or contaminated fluid can reduce the performance of the hydraulic system.
       
     • A clogged hydraulic filter can restrict fluid flow, causing the auxiliary system to underperform.
       
     • Leaks in the hydraulic lines or connections may result in reduced hydraulic pressure.
       
     • A malfunctioning pressure relief valve may not be properly regulating the hydraulic pressure.
       
3. Erratic Operation
   • Symptoms: If the front auxiliary hydraulics turn on or off without the operator’s input, or if they operate unpredictably, the issue may lie in the control switch or related components.
     
   • Possible Causes:
     • A faulty or damaged hydraulic switch that intermittently makes or breaks the connection.
       
     • Corroded electrical connections or worn wiring that can cause erratic behavior when the switch is activated.
       
     • An issue with the solenoid that controls the hydraulic flow to the front, which may fail to respond properly to the electrical signal from the switch.
       

Troubleshooting the Front Auxiliary Hydraulic Switch
When encountering issues with the front auxiliary hydraulic switch, it’s essential to perform a systematic diagnostic approach to isolate the problem. Below is a step-by-step guide for troubleshooting the system:

1. Check the Hydraulic Fluid
   • Why: Low or contaminated hydraulic fluid is a common cause of weak or sluggish hydraulic systems. Ensuring that the fluid is at the proper level and in good condition is the first step.
     
   • Solution: Inspect the hydraulic fluid level through the dipstick or sight glass. If the fluid is low, top it up with the recommended hydraulic oil. If the fluid appears dirty or contaminated, drain and replace it.
     
2. Inspect the Hydraulic Switch
   • Why: A malfunctioning hydraulic switch is a common issue, especially in older Bobcat 753 models. Over time, the switch can wear out, leading to erratic or non-functioning hydraulics.
     
   • Solution: Inspect the switch for visible damage or signs of wear. If the switch appears faulty or no longer clicks into place, consider replacing it. Ensure that all electrical connections are secure and free from corrosion.
     
3. Test the Electrical System
   • Why: The auxiliary hydraulic switch is part of an electrical circuit that communicates with the hydraulic solenoid. A failure in this circuit can prevent the hydraulics from working properly.
     
   • Solution: Use a multimeter to test the switch and the wiring. Check for continuity and inspect for any frayed wires, loose connections, or signs of short circuits. Replace any damaged wiring or connectors.
     
4. Check for Hydraulic Leaks
   • Why: Leaks in the hydraulic lines, fittings, or cylinders can reduce the system's pressure and cause a lack of power in the front auxiliary hydraulics.
     
   • Solution: Visually inspect the entire hydraulic system for signs of leakage. Pay close attention to hoses, fittings, and connections. Tighten any loose connections and replace damaged hoses or seals.
     
5. Inspect the Hydraulic Filter and Pressure Relief Valve
   • Why: A clogged hydraulic filter or a malfunctioning pressure relief valve can significantly impact the performance of the hydraulic system.
     
   • Solution: Inspect and replace the hydraulic filter if it appears dirty or clogged. Also, test the pressure relief valve to ensure that it is functioning correctly and maintaining proper system pressure.
     
6. Test the Solenoid
   • Why: The solenoid controls the flow of hydraulic fluid to the front attachment. A faulty solenoid can prevent the fluid from reaching the auxiliary hydraulics.
     
   • Solution: Test the solenoid to ensure it is receiving the electrical signal and opening/closing the fluid path correctly. If the solenoid is defective, it may need to be replaced.
     

Preventative Maintenance for the Bobcat 753
To prevent future issues with the front auxiliary hydraulic system and ensure optimal performance, regular maintenance is essential. Here are some tips for maintaining the system:

• Regular Fluid Checks: Periodically check hydraulic fluid levels and quality. Ensure that the fluid is clean and at the recommended level.
  
• Electrical System Maintenance: Inspect electrical connections and switches regularly for signs of corrosion or wear. Clean and tighten connections as necessary.
  
• Hydraulic Hose Inspections: Routinely check hydraulic hoses for signs of wear, cracks, or leaks. Replace any hoses that show visible damage.
  
• Scheduled Servicing: Follow the manufacturer's recommended maintenance intervals for oil changes, filter replacements, and other essential services.
  

Conclusion
The front auxiliary hydraulic switch on the Bobcat 753 is crucial for the efficient operation of a variety of attachments, making troubleshooting and maintenance of this system essential. By understanding the common issues that arise with the switch and hydraulic system, as well as following a systematic approach to diagnostics, operators can quickly identify and resolve any problems. Regular maintenance, such as fluid checks and electrical system inspections, will help extend the life of the Bobcat 753 and ensure that the front auxiliary hydraulics continue to function effectively for years to come.