Handling Hydraulic Hose Failures on Excavators

[MikePhua]

Hydraulic systems are the backbone of most heavy construction equipment, providing the necessary force to power various functions like lifting, digging, and rotating. Among these systems, the dipper or arm hydraulics are crucial components of excavators. A blown dipper hose can disrupt operations, leading to downtime and potentially causing significant damage if not dealt with promptly. In this article, we will explore the causes of hydraulic hose failures, common signs of a blown dipper hose, and steps for replacing the hose effectively.
Understanding the Dipper Hose and Its Role
The dipper hose is an essential component in the hydraulic system of an excavator. It connects the hydraulic pump to the dipper arm, which is part of the arm assembly that allows the excavator bucket to move. The hydraulic fluid in these hoses is responsible for actuating the hydraulic cylinders that lift, rotate, and extend the dipper arm.
As the excavator works in demanding environments, these hoses are under constant pressure and are susceptible to wear and tear. Any failure in the hydraulic system, such as a burst hose, can halt operations quickly and can be a costly inconvenience.
Causes of Hydraulic Hose Failure
Several factors contribute to the premature failure of dipper hoses in excavators:

1. Aging and Wear: Over time, hydraulic hoses can become brittle and prone to cracking, especially in harsh environments. Constant exposure to heat, cold, and extreme working conditions accelerates this process.
   
2. High Pressure: Hydraulic systems operate under high pressure, and a sudden spike in pressure can cause a hose to burst. This can be the result of an obstruction or a sudden surge in hydraulic fluid.
   
3. Improper Installation: Incorrectly routed hoses, improperly tightened fittings, or poorly designed connections can cause strain on the hoses, leading to premature wear or immediate failure.
   
4. Chemical Contamination: Hydraulic hoses are designed to handle specific types of fluids, and any contamination by incompatible fluids (e.g., dirt, water, or oils not suited for hydraulic systems) can weaken the hose material.
   
5. Physical Damage: During operations, hoses can be exposed to rough surfaces, sharp edges, or heavy objects that cause abrasions or punctures. Additionally, hoses that come into contact with hot surfaces can degrade rapidly.
   
6. Vibration and Flexing: Constant flexing and vibration, especially at the hose connection points, can weaken the hose over time, making it more susceptible to failure.
   

Signs of a Blown Dipper Hose
It’s essential to detect a blown dipper hose early to avoid further damage to the hydraulic system. Some common signs of a failed dipper hose include:

1. Loss of Hydraulic Power: A sudden loss of lifting power or difficulty moving the dipper arm can be an indication that the hydraulic system is losing pressure due to a blown hose.
   
2. Visible Oil Leak: A significant oil leak around the dipper arm or hydraulic cylinders is a clear sign that the hose has ruptured or split.
   
3. Erratic Movements: The dipper arm may move in an unpredictable or jerky manner, which could indicate that hydraulic fluid is not being delivered smoothly due to a hose rupture.
   
4. Unusual Noises: If there is a hissing sound or a noticeable drop in performance, this could point to hydraulic fluid escaping under high pressure through a burst hose.
   
5. Warning Lights: Many modern excavators have sensors and diagnostic systems that trigger warning lights when there is an issue with the hydraulic system. A hose failure could cause a warning or error code.
   

Steps to Replace a Blown Dipper Hose
Replacing a dipper hose is a relatively straightforward process, but it requires attention to detail to ensure it’s done correctly. Here are the steps for replacing the hose:

1. Safety First: Before starting, ensure that the excavator is turned off, and the hydraulic system is depressurized. Wear appropriate safety gear, including gloves and goggles, to prevent injury from high-pressure fluid or sharp edges.
   
2. Locate the Blown Hose: Inspect the hydraulic system to identify the damaged or burst dipper hose. Look for signs of leakage, and trace the hose from the hydraulic pump to the dipper arm to determine the exact point of failure.
   
3. Remove the Damaged Hose: Once identified, disconnect the hydraulic lines that are attached to the hose. Be sure to catch any residual hydraulic fluid in a suitable container to avoid contamination and environmental damage.
   
4. Install the New Hose: Using a replacement hose that matches the specifications of the original, install it into place. Ensure that the new hose is correctly routed, free from kinks, and properly tightened to the fittings. When connecting the hydraulic fittings, make sure they are secure but not overtightened to prevent damaging the threads.
   
5. Check for Leaks: After replacing the hose, test the hydraulic system by running the excavator through its normal operations. Check all connections for any signs of leaks, and ensure that the dipper arm moves smoothly and without interruption.
   
6. Top Up Hydraulic Fluid: If necessary, add hydraulic fluid to the system to bring the level back to normal. Always use the recommended fluid type for your equipment to ensure optimal performance.
   
7. Test for Full Functionality: Finally, operate the excavator through various motions to verify that the hydraulic system is functioning correctly. Pay special attention to the dipper arm’s responsiveness, checking for smooth movement and power.
   

Preventing Future Hose Failures
Preventative maintenance is key to avoiding recurring hose failures. Here are a few tips to extend the life of your hydraulic hoses:

1. Routine Inspections: Regularly inspect hydraulic hoses for signs of wear, cracks, or damage. Early detection can prevent catastrophic failures.
   
2. Replace Worn Hoses: If a hose shows any signs of wear, even if it hasn't fully burst, replace it before it becomes a bigger issue.
   
3. Clean Hydraulic System: Ensure that your hydraulic system remains free from contamination. Clean any debris that could damage the hoses, and use high-quality hydraulic fluids.
   
4. Proper Hose Routing: When replacing hoses, make sure they are routed properly to avoid rubbing against sharp edges or hot components. Ensure that they are securely fastened to avoid unnecessary movement and vibration.
   
5. Training Operators: Educate equipment operators on the importance of smooth, controlled operation to avoid unnecessary strain on the hydraulic system. Avoiding sudden movements or excessive loading can reduce the risk of hose damage.
   

Conclusion
Hydraulic hoses, especially those attached to critical components like the dipper arm on an excavator, are vital for the machine's efficient operation. A blown hose not only causes downtime but can lead to expensive repairs if left unaddressed. By identifying the cause of the failure, replacing the hose promptly, and performing regular maintenance, you can extend the lifespan of your hydraulic system and keep your excavator running smoothly for years to come.
Taking proactive steps to maintain the hydraulic system and keeping an eye out for signs of wear and tear will help prevent costly and time-consuming breakdowns on the job site.