10 Most Common Hydraulic Hose Failures and How to Solve Them

Essential to the smooth operation of various types of equipment and vehicles, hydraulic hoses are regularly subjected to various stresses and harsh environmental conditions. These can lead to hydraulic hose failure and potential damage to equipment/vehicles, costly hydraulic hose repairs, unscheduled downtime, and safety hazards in the workplace.

Understanding hydraulic hose issues and implementing appropriate preventive and corrective strategies can save you a lot of frustration and increase the service life of your hydraulic assembly and equipment. In this article, I’ll share some insights based on our years of hands-on experience, reviewing the most common hydraulic hose failures and how to resolve and prevent them.

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Hydraulic Hose Issues and How to Fix Them

1. Cover Abrasion

Problem: Cover abrasion occurs when the hydraulic hose repeatedly grinds against machine surfaces or other hydraulic components in its working environment, wearing down its outer cover. Over time, this wearing down may worsen, exposing the hose reinforcement layers and accelerating further damage, eventually leading to premature hose failure, which is often characterized by fluid leaks or hose bursts.

Note: Cover abrasion can also be caused by conveying non-compatible hydraulic fluids through the hose or the hose coming into contact with toxic chemicals, detergents, or acids.

Solutions:

• Re-route the hoses away from high-wear operating environments and exposure to non-compatible or toxic fluids. To do so, you can use clamps, spring guards, nylon ties, and bent tube couplings to bundle together the hoses that can flex in the same direction.
• Use protective sleeves (like polyurethane and nylon sleeves) and spring guards to protect your hose covers from wear, abrasion and consequent damage.
• Regularly inspect your hydraulic hoses for signs of outer cover wear and make the necessary changes, e.g., use a hydraulic hose whose outer cover is compatible with the chemicals it may be exposed to.

2. Hydraulic Hose Burst at Body

Problem: This failure mode occurs when a hydraulic hose breaks open or ruptures at some length away from its ends. It is often caused by:

• Pressure surges in the hydraulic system that exceed the maximum operating pressure a given hydraulic hose can handle – its rated working pressure.
• Excessive flexing or bending of a hydraulic hose beyond its specified minimum bend radius. This can create kinks that weaken the hose structure and restrict fluid flow, causing the hose to burst along its body.
• Extremely high system temperatures can cause a hydraulic hose to expand abnormally, leading to blockage and jamming issues in the hydraulic hose assembly, which may ultimately cause the hose to burst along its body.
• Long-term exposure to corrosive fluids can cause hydraulic hoses to become fluffy, deteriorate, and eventually burst.
• Bending a hydraulic hose tighter than recommended can exert excessive compressive and tensile stresses on the hose reinforcement, opening large gaps between the reinforcement strands and severely reducing the hose’s ability to withstand high working pressures.

Solutions: 

• Ensure that the operating pressures and temperatures of your hydraulic system are as recommended by the hose manufacturer.
• Select a hydraulic hose whose working pressure rating can safely handle the maximum operating pressure requirements, including pressure surges, of your hydraulic application.
• Install pressure-relief valves to help manage pressure surges in the hydraulic system.
• If your hydraulic system has recurring pressure surges, consider installing spiral wire-reinforced hydraulic hoses instead of wire braid-reinforced hoses.
• Re-route your hoses as necessary to avoid sharp bends and eliminate excessive flexing. Alternatively, you can use a hose with a smaller bend radius.
• Use hoses whose recommended minimum bend radii is appropriate for your application to prevent kinks.
• Prevent corrosive fluids from getting into contact with your hydraulic hoses and clean the outer hose surfaces more frequently.

3. Hydraulic Hose Crack

Problem: Exposing a hydraulic hose to high system temperatures above its maximum temperature rating can cause cracks to develop in the hose tube or cover. Essentially, an 18°F temperature increase beyond the recommended temperature range can cause the hose to become brittle (often appearing as hardened) and highly prone to cracking, consequently shortening its service life by half.

High system temperatures can result from routing the hydraulic hoses near a heat source like an exhaust manifold or using an undersized reservoir tank or hydraulic hose.

In addition, a hydraulic hose can develop cracks when it is exposed to extremely low temperatures, below the recommended limits, especially in very cold winters. Bending/flexing the hose beyond the stipulated minimum bend radius can also cause hose cracks.

Solutions: 

• Inspect your hydraulic hoses for cracks and replace them immediately if cracks are noted.
• Review the temperature and flow rate requirements of your hydraulic application and select hydraulic hoses that can appropriately meet those requirements.
• Identify nearby heat sources (e.g., exhaust manifolds) and re-route your hoses away from such to minimize exposure to excessive heat.
• Examine the size of the reservoir tank and replace it if need be.
• Raise your system’s operating temperature to within the approved range or replace existing hydraulic hoses with the ones recommended for lower operating temperatures.
• Pay attention to the specified bend radius of each of your hydraulic hoses.

4. Hydraulic Hose Blistering

Problem: Hydraulic hose blistering is when blisters, bubbles, or bumps form on the hose cover due to a number of factors, including fluid contamination, trapped gases or air, excessive system pressure, improper curing during hose manufacturing, or exposure to extreme heat.

For instance, you may see swellings on the surface of a hydraulic hose because of incompatible hydraulic fluids permeating the hose tube and collecting under its cover. Compressed gases may also effuse through the hose tube and get trapped under the hose cover, causing bubbling or blistering. Blisters can also arise when too much air gets trapped in the spaces between the inner hose tubing and outer cover.

Solutions:

• If the existing hydraulic hoses are not compatible with the hydraulic fluids being transmitted, replace them with compatible ones.
• If the blistering is being caused by compressed gases, perforate the hose cover to allow the trapped gases to percolate through the cover.
• Bleed your hydraulic system regularly to expel any trapped air.
• Using textile braid-reinforced hydraulic hoses can also help eliminate blistering.

5. Tube Swell

Problem: The inner tube of a hydraulic hose can swell and deteriorate, causing the connected hydraulic equipment or machinery to slow down or become unresponsive. Hose tube swelling is mainly caused by:

• Incompatible hydraulic fluids are the primary cause of hose tube swelling, delamination, and deterioration. At times, the tube may also become partially washed out in some sections, which is only notable if the tube is cut open and inspected.
• Very high fluid temperatures can cause the hose tube to bulge or swell near the end of the hose coupling.
• Improper hose assembly. Modifying the OEM (Original Equipment Manufacturer) design of a hydraulic hose assembly by increasing or reducing the size of a hydraulic hose or altering the coupling configuration can cause hose tube swelling.

Solutions:

• Replace the hydraulic fluid in use with one that is compatible with the hose tube material, or replace the hydraulic hose with one whose inner tube material is compatible with the system’s hydraulic fluid.
• Select a replacement hose that can withstand the temperature of the hydraulic fluid being conveyed.
• Replace the existing hose assembly with OEM-specified hose sizes, fittings, and couplings.

6. Hose Twist

Problem: A hose twist problem is identified by a spiraling hose layline with the hose bending in two planes. Bending a hydraulic hose in multiple planes (e.g. two planes) causes its reinforcement to twist and misalign, therefore reducing its ability to withstand high working pressures, ultimately leading to system-wide pressure losses and reduced system performance.

A hose twist as small as 5° can reduce the service life of a hydraulic hose rated for high-pressure operations by 70%, while a 7° hose twist can reduce the service life of a comparable hose by 90%. Twisted hoses can also develop micro-fissures and fissures, leading to fluid leaks that can compromise the efficiency of a hydraulic system and pose safety and environmental risks.

Solutions:

• Replace the twisted hoses and re-route the new ones to ensure that bending will only occur in one plane. Using block-style hose adapters and couplings or bent hose tubes can help improve the routing process.
• During installation, align the hoses properly using the layline as the reference to avoid twisting.
• If you’re using male and female hose couplings on the same hydraulic hose assembly, be sure to install the male end (non-swivel end) first.
• Using flexible supports and swivel-type hose fittings can significantly reduce the risk of hose twists.

7. Hose Burst at Coupling

Problem: This is a type of hose failure that occurs at the connection point between the hydraulic hose and coupling. It is usually caused by an over-crimped hose end, excessive hose bending/flexing, over-tightening of the hose coupling, inadequate hose slack, incompatible hose-coupling materials, or improper assembly. The problem is especially common in high-pressure hydraulic systems, whereby the hose shrinks in length, putting enormous stress on the coupling.

Solutions:

• Replace the hydraulic hose assembly with properly crimped couplings and hose ferrules.
• Use the recommended assembly techniques and torque specifications when connecting couplings to hydraulic hoses.
• Ensure the compatibility of the hydraulic hose material and coupling.
• Increase the hose length, as recommended by its manufacturer, to allow for contraction under high working pressures.
• Extend the actual bend radius of the hydraulic hose as it exits the coupling for proper hose-coupling assembly and routing.
• Use bend restrictors to reduce the amount of bending stress exerted onto the coupling.

8. Hose Weeping at Coupling Interface

Problem: Visible dripping or seeping of hydraulic fluid from the end of the coupling ferrule is often caused by improper fitting selection, excessive hose flexing/bending, damaged sealing elements, under-crimping or over-crimping, or insufficient clamping force. Excessive vibrations, wear and tear of the sealing surfaces at the hose-coupling interface, and failure to insert the hydraulic hose fully during assembly can also cause hose weeping at coupling interface.

Solutions:

• Replace the assembly of the hydraulic hose if it has been over-crimped or under-crimped or if the hose was improperly inserted.
• Replace damaged or worn-out sealing elements with new seals to ensure a leak-free hose-coupling connection.
• Ensure that the hose and coupling are properly assembled by using the recommended tightening torque values and following the manufacturer’s installation guidelines.
• Regularly inspect the hose and coupling for wear and tear and replace each component as necessary.
• Match the hydraulic hose with a coupling of the same type and size to establish a secure and leak-proof connection.
• Store your hydraulic hoses and couplings in a cool, clean, and dry environment to prevent damage or degradation by external factors.

9. Coupling Blow-Off

Problem: A crimped hydraulic hose coupling can come off the hose end due to excessive system pressure, over- or under-crimping, incompatibility issues, inadequate clamping force application, or improper hose-coupling assembly. The problem can also be caused by the use of incorrect crimping dies, failure to allow enough hose slack during the routing process, or improper hose skiving (if applicable).

Solutions:

• Modify the length of the hydraulic hose and/or routing strategy to allow for possible hose shrinkage when the hose is under high system pressure.
• Inspect the hydraulic hose assembly and replace it according to manufacturer guidelines, including the use of recommended assembly tools, proper crimping, and tightening the hose couplings to the specified torque values.
• Verify that the couplings correctly match the hose specifications and are compatible with the hose type or material.
• Utilize reliable, high-quality hose couplings, such as carbon steel and stainless-steel couplings, suitable for high-pressure hydraulic applications.

10. Hydraulic Hose Leaking at Fitting

Problem: Hydraulic hose leaking at the fitting connection is normally caused by a damaged or missing O-ring, incorrect fitting installation, an under-/over-torqued fitting, or the use of an incompatible hose fitting. This problem can result in reduced system performance, fluid loss, and potential safety hazards; it should thus be addressed promptly.

Solutions:

• Reassemble the hose-fitting assembly, applying the correct amount of torque on the assembly.
• Replace damaged or missing O-rings.
• Clean the surface around the leaking hose fitting to remove any debris, dirt, or accumulated hydraulic fluid. This will help ensure a better seal when a hydraulic sealant is applied.
• Use a high-quality hydraulic sealant appropriate for your hydraulic system and the specific type of hose fitting in use.
• Ensure the compatibility of the hydraulic hose material and fitting.

The ten hydraulic hose failures listed above are some of the most encountered in the industry. However, there are more such-like issues, mainly related to improper hose/coupling assembly and incorrect installation of hose fittings.

Best Practices to Prevent Hydraulic Hose Failure

At Marshall Equipment, we’ve learned that the best way to avoid hydraulic hose failures is by taking a proactive approach. Here are some best practices that will help you keep your hydraulic systems running smoothly.

Perform Regular Inspection and Maintenance

Conducting regular inspections of the entire hydraulic hose length, paying close attention to sections that are prone to stress, bending, or abrasion, can help you identify early signs of wear, degradation, or damage. This enables you to take proactive measures, carry out timely replacements and complete hydraulic hose repairs, reducing the risk of unexpected hose failures.

Select The Right Hose for the Job

You need to select your hydraulic hose based on the appropriate temperature and pressure ratings, environmental specifications, and minimum bend radius for your hydraulic system. Manufacturers like Gates provide such ratings and specifications to ensure optimal performance, flexibility, and durability of their hoses under different operating conditions. Consulting with hydraulic experts (at Marshall Equipment, we have some pretty good ones) can also assist in selecting the perfect hose for your hydraulic system.

Ensure Proper Hose Assembly

Always consult and follow the manufacturer’s instructions and guidelines for proper hydraulic hose assembly, including recommended hose lengths, fitting/coupling types, bending radius, appropriate torque specifications for couplings and fittings, and recommended assembly tools and techniques. This will ensure secure, leak-free, and reliable hydraulic connections.

Protect Your Hose from Extreme Conditions

In hydraulic applications where hoses are likely to be exposed to extreme temperatures, consider insulating the hoses using a material with excellent resistance to heat. Similarly, the use of UV-resistant insulation and spiral guard wraps will protect your hoses from UV light.

For chemical protection, you can choose hydraulic hoses made of chemical-resistant materials, like Polytetrafluoroethylene (PTFE or Teflon®), Polyvinyl Chloride (Vinyl or PVC), Polyethylene, Viton™, Polyurethane, Santoprene™, and Silicone rubber.

Ensure Fluid Compatibility

Incompatibility between the hydraulic fluid and hose material can lead to hose tube degradation, compromising the integrity and safety of your hydraulic system. As such, always use the specific hydraulic fluids recommended by the hose manufacturer. In addition, I strongly recommend proper storage and handling of selected hydraulic fluids to prevent contamination.

Train and Educate Your Team

As a hydraulic hose specialist, I consider it essential to fully train your hydraulic system operators and maintenance personnel in hose handling techniques, safety precautions, and proper maintenance to prevent hose failures. It is also important to equip your team with the knowledge and skills to quickly spot potential hose issues and implement preventive measures correctly.

Keep Records

When it comes to hydraulic systems, it is good practice to keep a detailed hose inspection log that includes inspection dates, key findings, any corrective/preventive actions taken (e.g., replacements or repairs), and the name of the hydraulic technician conducting the inspection. Such records help your maintenance team monitor the performance and assess the overall health of each hydraulic hose, identify potential issues, and make well-informed maintenance decisions.

Stock on Spare Hoses and Fittings

Maintaining an in-house inventory of spare hydraulic hoses and fittings will help ensure that these components are replaced proactively, as recommended by the hose manufacturer, before the end of their service life. It can also help reduce the duration of maintenance downtime and productivity losses.

Be Prepared for Emergencies

I recommend that you equip yourself with quick-fix hydraulic hose repair kits. These kits are designed to help hydraulic system operators resolve hose issues promptly and effectively without the need for specialized tools or extensive training. Besides, having access to on-call hydraulic maintenance services can help reduce system downtime in the event of a major hose failure.

Conclusion

Understanding the nature, causes, and effects of common hydraulic hose failures will make it easier for you to implement the appropriate preventive and corrective measures essential to maintaining the integrity and reliability of your hydraulic system.

In addition, by prioritizing periodic hose inspections, preventive maintenance, correct hose selection and assembly, fluid compatibility, hose insulation, and proper personnel training, your company can improve the performance and reliability of its hydraulic systems, prevent equipment damage, reduce unplanned downtime and associated costs, and ensure workplace safety.

In the event of hydraulic hose failure, you can count on Marshall Equipment to help you minimize downtime. Our team is ready to assist with our extensive inventory of hydraulic hoses, couplings, fittings, and adapters, as well as our hydraulic hose repair and assembly services. Contact us for more information.

Note: The information and images used in this article are based on Gates’ Guide to Preventive Maintenance & Safety for Hydraulic Hose & Couplings.