Hydraulic hose failure is a serious matter, no matter what industry or type of equipment is involved. Hose failure causes the shutdown of machines and entire systems, resulting in downtime, expensive repairs, and other financial losses. If high pressures are involved, there is a potential physical danger to employees when hoses fail. This article discusses the seven most common causes of hydraulic hose failure and how to prevent them.
Hoses are not stationary – they will contract or stretch as the pressure within them changes. When hoses rub against objects, including other hoses but especially metal edges, this can result in abrasion. Abrasion is a very common cause of hydraulic hose failure and occurs when the outer cover of a hose is worn away to the point of exposing the reinforcing steel wires. This can eventually result in leaks.
To minimize abrasion, some hoses have plasticizers added to the material that makes up the hose cover. If there are specific problem areas, a plastic guard or nylon sleeve can be used to protect the hose.
Another major cause of hydraulic hose failure is poor routing. Avoid routing a hose through a potentially abrasive area or a pivot point. Do not route hoses through high temperature areas unless there is no alternative. Pay close attention that the minimum bend radius is met to avoid buckling, kinks, and failure.
If the hose is likely to be subject to a considerable amount of movement, consider the use of a swivel on the end of it. In short, use alternate routes, longer hoses, or different fittings as needed and plan the routing that will cause the least amount of abrasions or bends.
High Temperatures and Heat Aging Cause Hydraulic Hose Failure
When hoses are exposed to extreme temperatures, they begin to lose their flexibility and stiffen. High temperatures cause the plasticizers in the elastomeric inner tube to break down, which then hardens and begins to crack. As time goes by, those cracks can eventually reach the outside of the hose. If you remove a hose and it makes a cracking sound when you bend it or if it remains in a bent shape, then the problem is heat aging.
To minimize the effects of heat aging, avoid unnecessarily running hoses through high temperature areas and verify that the hoses are rated for the appropriate continuous operating temperature. If heat exposure cannot be avoided, consider the use of heat guards over the hoses.
Internal tube erosion is typically caused by concentrated high velocity streams of fluids (possibly with the presence of particles) that gradually erode the inner tube of the hose. As the erosion continues, an external leak can develop.
One of the best ways to prevent tube erosion is to determine the correct size of hose for the maximum expected fluid velocities. Another way to minimize the effects of tube erosion is to verify that the abrasiveness of the fluid is compatible with the type of hose used.
Bent Hoses and Failures at the Fitting
Another common area of hydraulic hose failure occurs at the fitting where the hose and crimp seal meet. This is usually caused by the hose being bent too closely to the actual fitting due to poor routing or the weight of the hose itself.
A good solution to this problem is the use of a bend restrictor, which is a plastic or rubber sleeve about six inches long that is more resistant to bending than the hose itself. It adds additional support to the hose in problem areas.
Not all fluids and hydraulic hoses are compatible. If an incompatible fluid is used with an otherwise excellent quality hose, it can cause the hose to begin to disintegrate from the inside, swell, and delaminate. If the hose disintegrates and leaks, serious particulate contamination to the hydraulic system can occur.
Make sure that all hydraulic hoses in use are compatible with the fluids running through them.
Improper assembly is another cause of hydraulic hose failure. When the hoses are cut to size, they must be carefully cleaned and flushed to prevent contamination by abrasive debris that is left behind. The inner tube should be as clean as possible, and the ends of the hoses should be clamped after the fittings have been crimped into place.
The Importance of Preventative Maintenance for Hydraulic Hose Failure
Many hose failure problems can be addressed by making sure the hoses are compatible with the environment in which they will be operating (e.g., heat, fluids compatibility, abrasion). Others involve careful routing and assembly procedures. However, the majority of hydraulic hose failures can be identified and mitigated through routine preventative maintenance.
For example, preventative maintenance makes it easy to spot hoses that are showing signs of abrasion or recognize areas where routing could be improved. Preventative maintenance is one of the keys to minimizing problems arising from hydraulic hose failures.
Preventative Maintenance from a Trusted Hydraulic Repair Facility
At MAC Hydraulics, we have trained and experienced technicians available to perform the preventative maintenance your business needs. We will troubleshoot your hydraulic systems and replace your hydraulic hoses as necessary. Our reliable staff has the experience and know-how to keep your systems running at optimum efficiency with maximum reliability and minimum downtime. We offer on-site repair and emergency services – we will bring our portable shop to you. Contact us today to see what we can do for you!