Adjusting Hydraulic Pressure to the Auxiliary System: A Comprehensive Guide

[MikePhua]

Hydraulic systems are at the heart of many heavy equipment machines, ensuring smooth operation and efficient performance. On machines like compact track loaders, skid steers, and backhoes, the hydraulic pressure settings are crucial, especially when dealing with attachments that require varying levels of hydraulic force, such as augers, hydraulic hammers, and grapples. The ability to adjust hydraulic pressure to the auxiliary system is a key skill for maintaining equipment functionality and maximizing attachment performance.
This guide delves into the importance of adjusting hydraulic pressure to the auxiliary system, how to do it safely, and why it is necessary for optimal machine performance.
Understanding the Hydraulic Pressure System
Hydraulic systems work by using fluid to transmit force from one location to another. These systems rely on a pump to push hydraulic fluid through the system, generating pressure that powers cylinders, motors, and other components. The pressure in the system determines how much force is delivered to the attached implements or work tools.
In most heavy equipment, the auxiliary hydraulic system is used to power various attachments that require hydraulic force to operate. These systems often have a dedicated hydraulic circuit with specific pressure settings to match the requirements of the attachment being used.
Why Adjust Hydraulic Pressure to the Auxiliary System?
Adjusting the hydraulic pressure to the auxiliary system is essential for several reasons:

1. Attachment Compatibility: Different attachments have specific hydraulic requirements. For example, a hydraulic thumb may require a different pressure than a trenching bucket. Properly adjusting the pressure ensures that each attachment receives the optimal force for operation.
   
2. Efficient Operation: If the pressure is too high or too low, the attachment may not perform optimally. Too much pressure can lead to premature wear or damage to the attachment or hydraulic components, while too little pressure can result in weak or sluggish performance.
   
3. Preventing Damage to the Machine: Incorrect hydraulic pressure settings can cause unnecessary strain on the hydraulic system, leading to overheating, pump failure, or other costly damage.
   
4. Safety: Hydraulic systems that operate outside their recommended pressure range can become dangerous. Over-pressurization can lead to hose ruptures or unexpected attachment movements, both of which pose safety risks.
   

Common Signs of Incorrect Hydraulic Pressure
Before diving into how to adjust hydraulic pressure, it’s essential to understand the signs that may indicate your auxiliary hydraulic pressure needs adjusting:

1. Weak Performance: If the attachment feels slow to respond or lacks power, this may indicate that the pressure is too low.
   
2. Excessive Noise: Hydraulic systems that are operating under high pressure often make a loud whining noise. Conversely, systems with low pressure might not make much noise at all, but may still exhibit sluggishness.
   
3. Overheating: Incorrect hydraulic pressure can cause the fluid to overheat, leading to poor performance and potential damage to seals, hoses, or the pump.
   
4. Leaks: Hydraulic pressure that is too high can cause hoses or fittings to leak, especially at pressure points where the system is designed to handle lower pressures.
   
5. Attachment Failure: If the attachment isn't working at its full capacity (such as a grapple that doesn’t fully open or a hammer that doesn't strike hard enough), this could be a result of improper hydraulic pressure.
   

How to Adjust Hydraulic Pressure to the Auxiliary System
Adjusting the hydraulic pressure to the auxiliary system may vary depending on the make and model of the equipment. However, the general principles remain the same across most machines.
Step 1: Identify the Pressure Adjustment Location
Most modern machines with adjustable hydraulic pressure will have a dedicated control valve or pressure relief valve for the auxiliary system. This is typically located near the hydraulic pump or manifold, often marked with a label indicating it is for the auxiliary circuit.
For machines that use variable displacement pumps, the pressure adjustment valve is usually found in the hydraulic compartment, often near the pump assembly or hydraulic manifold block.
Step 2: Use the Operator’s Manual for Reference
Before making any adjustments, it’s crucial to consult the operator’s manual for the correct pressure settings for your specific machine and attachments. The manual will typically provide:

• Recommended pressure settings for various attachments.
  
• Maximum allowable hydraulic pressure.
  
• Adjustment procedures specific to the make and model.
  

These settings are important for ensuring the safety of both the machine and its operator.
Step 3: Use a Hydraulic Pressure Gauge
A hydraulic pressure gauge is an essential tool for ensuring that your adjustments are accurate. You can either use a dedicated gauge on the machine (if it’s equipped with one) or attach a pressure gauge to a port in the hydraulic system.
To check the pressure:

1. Start the machine and operate the auxiliary circuit to ensure it is under load.
   
2. Read the pressure on the gauge while the system is operating.
   
3. Adjust the pressure on the relief valve or control valve as needed until the desired pressure level is reached.
   

Step 4: Adjust the Pressure Relief Valve
The pressure relief valve is often the main point for adjusting hydraulic pressure. Turn the valve clockwise to increase pressure or counterclockwise to decrease it. After making the adjustment, always check the gauge to ensure that the correct pressure is reached.
Step 5: Test the System
After making the adjustment, operate the attachment to ensure it is functioning correctly. Pay attention to:

• Speed and responsiveness: The attachment should respond smoothly and quickly.
  
• Attachment performance: Ensure that the attachment performs the way it’s intended (e.g., fully extending, lifting, or moving with full force).
  

If the attachment still performs poorly or you notice any of the issues mentioned earlier (e.g., overheating, slow response), you may need to further adjust the pressure or check for other issues, such as worn-out hoses or seals.
Step 6: Double-Check the System After Use
Once you’ve completed the adjustment and verified proper operation, it’s good practice to recheck the hydraulic system after a period of operation. This ensures that the pressure remains stable and that the hydraulic system is operating as expected.
Maintenance Tips for the Auxiliary Hydraulic System
Proper maintenance is crucial for the longevity and efficiency of the auxiliary hydraulic system. Follow these tips to avoid issues with hydraulic pressure adjustments in the future:

1. Check hydraulic fluid regularly: Low fluid levels can affect pressure. Always keep the system topped up with the correct type of hydraulic fluid.
   
2. Inspect for leaks: Regularly check hoses, connectors, and fittings for signs of leaks. Even small leaks can lead to pressure drops and performance issues.
   
3. Clean hydraulic filters: Dirty or clogged filters can cause increased pressure and overheating. Clean or replace filters as needed.
   
4. Keep the system free of contamination: Dirt and debris can damage the hydraulic components. Always ensure that fittings are securely connected, and that hoses are kept clear of contamination.
   
5. Consult the operator's manual: Always refer to the manufacturer’s guidelines for optimal pressure settings and maintenance schedules.
   

Conclusion
Adjusting hydraulic pressure to the auxiliary system is a straightforward process that plays a crucial role in optimizing the performance of your machine’s attachments. Proper adjustments not only ensure efficient operation but also prevent damage to both the machine and its attachments. By following the correct procedures, using the right tools, and performing regular maintenance, you can extend the lifespan of your equipment and keep it operating at peak performance for years to come.