Hydraulic Hose Replacement: How To Stay Ahead Of Failure

Stainless steel, PTFE, and Teflon hoses designed for hydraulic applications are flexible and incredibly durable to carry pressurised hydraulic fluids to or from motors, pumps, valves and other components. But despite their robustness, the pressure cycles they endure from normal operations and natural degradation eventually lead to failure.

Should failure occur unexpectedly, a host of dire consequences may follow. Thus, to prevent such incidents, many hose manufacturers recommend being proactive when it comes to replacement, i.e. replacing hoses once they are nearing the end of their service life but just before they fail.

Knowing when it is time for a replacement can be easier said than done – it is not always clear to see when a hose is starting to fail. Hence, we go over what you need to know to develop a timely hose replacement schedule.

 

Factors that influence the life expectancy of hydraulic hoses

 

1. Size

Hose sizes differ according to a system’s anticipated flow rate requirements, and it is crucial to know their limitations to avoid excessive velocity and flow rate. The former can damage the hose’s inner linings and other system components due to tube debris, while the latter increases the fluid’s temperature due to friction. As such, use the hose OEM’s nomograph as a guide to safely size the hoses for your system’s pressure and return circuits upon deciding on the pump output flow rate.

 

2. Temperature

Most rubber hoses are typically designed to operate at temperatures ranging from -40°C to 100°C. In comparison, other hose materials can perform up to 150°C and beyond, such as PTFE tubed hoses, which safely operate at 232°C. However, ambient conditions or hydraulic fluids outside of this range can result in premature failure.

The cooler the fluids used in the hose (well below its rated maximum), the longer it can stave off material degradation. Lastly, hoses should be shielded from external heat sources like engine manifolds to prevent damage to the hose and cause a fire hazard.

 

3. Pressure

Hydraulic hoses have a maximum working pressure rating that determines which applications they are suitable for without the risk of permanent damage or failure. It is generally a best practice to choose hoses rated a few hundred psi greater than the application’s maximum working pressure to ensure the latter never exceeds the former’s rating.

 

4. Application

Each hydraulic hose is designed for use in a specific array of functions and duty cycles. However, they can still be damaged by various factors related to their application, even when used properly. For instance, hoses used in vertical installations experience more stress compared to those placed horizontally, while hoses used indoors may be subjected to higher temperatures, especially when they are installed near ovens or furnaces. While many of these conditions are unavoidable, proper installation and protective measures like shielding can significantly extend a hose assembly’s service life.

 

5. Fluids

When choosing a hydraulic hose assembly, make sure that its construction materials are compatible with your application’s hydraulic fluid. This can be determined by checking the fluid’s Material Safety Data Sheet and the hose manufacturer’s compatibility listings. It should go without saying that using incompatible materials will compromise system performance and, worse yet, damage the assembly as well as other components.

 

Signs that indicate a hydraulic hose needs replacement

While it is often difficult to know when a hose assembly needs to be replaced, some visual indicators tell when a hose is at the end of its service life, such as:

• Distorted or crushed hoses
• Fluid leaks within the fitting ends or anywhere within the length of the hose length
• Kinks and twisted hoses (which indicate incorrect routing)
• Exposed wire reinforcement
• Substantial surface damage
• Corroded fittings
• A blistered or hardened cover and any signs of the cover softening significantly, which typically means fluid incompatibility

 

How to replace hydraulic hoses

The replacement process for a hydraulic hose is as follows:

 

1. Identify the issue and assess the situation

First and foremost, thoroughly verify the damage to the hose to ensure that any planned repairs or replacements actually address the problem. Then, check which system components must be removed to proceed with the replacement.

 

2. Prepare the system

Get all the parts connected to and around the hose out of the way so they do not get in the way. Also, consider photographing the hose’s routing beforehand so the replacement can be put back in place properly.

 

3. Loosen the fittings and remove the hose

Once everything is prepared, loosen the fittings, remove the hose, and pour the leftover residual fluid into a container.

 

4. Seal the fittings

Before installing the new hose, seal the fittings first using a rag or designated fitting plug to avoid leakage.

 

5. Install and visually check the new hose

Properly install the replacement hose by referring to the OEM’s instructions and torque recommendations, and then reassemble the rest of the system. Afterwards, visually inspect the hose to double-check whether it is routed and connected properly.

 

6. Test the system

Finally, do some tests once the system is reassembled to ensure no leaking or performance issues.

 

Conclusion

As with everything else in a facility, hydraulic hoses will fail at some point. Preventing this failure from affecting facility operations and equipment necessitates proactive measures like the ones outlined above. To maximise your hose’s replacement intervals, you can always reach out to the hose distributor or OEM manufacturer for insight into the expected working life of their products. But if a hose is beginning to show signs of wear or degradation, replacement should not be delayed.