Whether you are running hydraulic equipment or creating hydraulic assemblies, you’ll see some common hose failures during your career. If you are encountering hydraulic hose failure, check out these common failure modes and their solutions. By understanding what’s causing the hose to fail, you’ll be able to make better decisions in regards to future usage and replacement.
Cover abrasion occurs when part of the hose cover has been removed, exposing the hose reinforcement. This may be caused by non-compatible fluids or continuous rubbing against objects in the operating environment. Exposed hose reinforcement is susceptible to rust and accelerated damage.
Solution: Re-route the hose by bundling hose together that flex in the same direction. Protect the hose cover from abrasion with nylon and urethane sleeving and spring guards.
Gates offers hose covers with far greater abrasion resistance than any standard rubber hose in the industry. Gates MegaTuff® has 300X the abrasion resistance of standard hydraulic hose, while Gates XtraTuff™ has 25X the abrasion resistance and ½ the bend radius of standard hydraulic hose.
Hose Burst at Body
A hose bursting at some length away from the hose ends may be caused by excessive pressure surges, flexing, kinking, crushing or exceeding minimum bend radius.
Solution: Review/inspect your operating pressure. Select a hose that has the proper working pressure rating to handle the maximum pressure (including surges) of your application. Reroute hose to eliminate excessive flexing and/or exceeding the minimum recommended bend radius for the hose in use.
Gates MegaSys® hose products are designed to improve flexibility and bend up to 1/3 the industry standard (SAE) specification.
Hose Burst at Coupling
A hose burst at the coupling end may be caused by insufficient hose slack, excessive bending/flexing or an over-crimped hose end.
Solution: Increase the assembly’s hose length to accommodate contraction under pressure and increase actual bend radius as the hose exits the coupling. Bend restrictors can also be used to reduce bending stress at the coupling. Replace hose assembly with properly crimped assembly.
Hose/Coupling Interface Weep
Fluid seeping or weeping from the end of the ferrule may be caused by insufficient hose insertion during assembly and/or under-crimping. Also, excessive vibration, flexing and tugging may weaken the interface and reduce the assembly’s ability to prevent fluid seepage.
Solution: Whether it has been under-crimped or the stem has been improperly inserted, the hose assembly must be replaced with one that has been properly assembled. Gates MegaCrimp® couplings have been designed to provide weep-free performance as well as easy/simple insertion.
The most frequent cause of coupling blow-off (where the coupling has separated and released from the hose) is improper assembly.
Solution: Examine and replace the hose assembly to ensure proper procedures are followed. Modify hose length and/or routing to accommodate potential hose length reduction under pressure. And remember to never mix manufacturers’ hose couplings or crimpers!
A hose cover or tube with cracks is typically caused by exposure to excessive heat and/or ozone. Did you know an increase of just 18°F above the maximum temperature may decrease hose life by 50%? Cracks can also be caused by flexing, especially at excessively low temperatures.
Solution: Select a hose that meets the temperature and flow requirements of the application. Also, identify the heat source and consider re-routing it away from the source to minimize the heat’s effects.
Hose twist is evident by a spiraling hose label and bends in two planes. Twisting a high-pressure hose 7° may reduce the service life up to 90%!
Solution: Replace and re-route the hose to ensure that bending occurs only in one plane.
If the equipment has become sluggish and unresponsive, cutting and evaluating the hose will probably show that the hose tube is swollen, deteriorated and possibly washed out in sections! Fluid incompatibility is the likely cause. Excess fluid temperatures can also cause the tube to bulge near the end of the coupling.
Solution: Replace the hose using a tube material recommended for that particular fluid.
Blisters that have formed on the hose cover can be caused by incompatible fluids that have permeated the hose tube and collected under the cover. Compressed gases can also permeate or effuse through the tube and become trapped under the cover.
Solution: Replace the hose with one that is recommended as compatible with the fluid being used. If it is compressed gas, the cover can also be perforated to allow the gas to pass through the cover.
Other common failure modes include: thread leaks, crushed hose, coupling corrosion, hose tube cracks and crimping errors. Gates Hydraulics has been powering progress for a wide range of industries for years. Our hydraulic hose systems excel even under the toughest conditions. Whether you’re in need of hose, couplings or crimpers, Gates’ hydraulic products are engineered for high performance and cost savings. For more information, click here.