All industrial products have a service lifespan during their application, hydraulic hoses are no exceptions, due to adverse impacts such as wrong selection of hose size, environmental factors related to application, and incorrect hose assemblies, hydraulic hoses deteriorate gradually from the date they are manufactured, and then the questions come out, when and how to replace a hydraulic hose, do they have any signals to indicate when they are going to be replaced? in this article, I will walk through the hints that a hydraulic hose should be replaced and how to replace them step by step.
Why do hydraulic hoses deteriorate during their life?
- Hydraulic fluid corrosion: when selecting hydraulic hoses for your hydraulic system, all the construction materials should be compatible with the hydraulic fluid, an incorrect match will damage the hydraulic hose, corrode and degrade the rubber, and decrease the lifetime prematurely.
- Hydraulic fluid flowrate in the inner hose: Excessive velocity will damage the inner surfaces of the hose, what’s more, excessive flowrate will raise the temperature of the hydraulic fluid owing to friction, as the heat accumulates, it will the rubber and even the reinforcement, and do harm to the overall construction. you can refer to the nomogram to determine the size of your hydraulic hose.
- The impulse pressure: The cyclical impulse pressure can damage the reinforcement layer and fatigue the rubber, so it is critical to ensure the real working pressure is below the rated working pressure, even the pressure spike should be lower than the rating pressure. excessive pressure will increase the likelihood of hose failure.
- The temperature of hydraulic fluid and ambient environment: If your machine works for a long time or at high velocity in the inner hose, the hydraulic fluid will accumulate more heat due to the frications or the heat derives from the ambient heat resource, all these factors will heat the rubber hose, high temperature will lead to the hose becoming hard, brittle and cracked. adversely, the excessive cold temperature will also lead to the hose becoming stiff, hard, and premature. the most hydraulic hoses rated temperature is in the range of -40°F to 212°F.
- Abrasion between the hydraulic hose and other components: Most hydraulic hoses are not static in place of their original position, especially in mobile equipment, cyclical movement can lead to the hose rubbing with other components or hoses, and these frictions result in abrasion and wear on the surface of the hydraulic hose.
- Twisting and kinking because of the vibration: As mentioned above, relative movement may cause the hydraulic hose to twist and kink due to the change in the original layout, these twist and bend are always unexpected and pose extra force to the hydraulic hose and lead to hose damage partly.
- UV rays and ozone can damage the rubber: UV rays in the sunshine and ozone in the air can corrode the rubber as time goes by. and these factors can make the carbon to carbon key break in the rubber morecullar, and lead to the crack on the rubber surface.
Signals to indicate hydraulic hoses should be replaced.
Some visual cues can give you a signal to replace a hydraulic hose in your machine, which are the results from the described reasons above, once the Phenomenon come out, it it the time for you to change a new one.
- Cracks on the hose surface.
- Tears or abrasions.
- Exposed wire reinforcement.
- Fluid leakage within the hose length or at the end.
- Crushed deformance of the hose.
- Twist and kinks on the part of the hose.
- Corroded fittings
How to replace a hydraulic hose step by step?
When you observe some leakage or defects on the hydraulic hose, you can determine it is time to replace a hydraulic hose, on the procedure, you should follow the description below:
Indentify the right hydraulic hose to replace the old one:
Before changing the old hydraulic hose, you should figure out the demensions and specifications, the inner diameter, the working pressure, the length of the hose, the connectors type, thread type and seal type as so on, bear them in your mind, and choose the right elements to make a hydraulic assembly.
Take photos for the section which amending is needed:
Before removing the old hoses from the machine, remember take photos for the layout and the status of the hoses in order to reffer to after change is complete and restore to it original status.
Wear your gears like gloves, sleeves, and clothes to protect your body:
Hydraulic fluids tend to be toxic, these may contaminate your skin or even hurt it, so it is vital to wear your face mask, gloves, sleeves, and working clothes and keep your skin not exposing to avoid splashing hydraulic fluid hurt your body.
Make enough rags available and ready to wipe off the dirt and oil on the connectors:
It is cheap way to prepare sufficiant rags when taking up maintian work, of course, it is neccessary to do that. Rags can absorb oils effeciently and wipe off the dirt easily, when the hydraulic hose is being teared down , the remaining fluid can be wiped off with rags on time.
Relieve the pressure of the hydraulic system and ensure the hydraulic fluid not splash out:
Hydraulic fluids are always pressurized during the application, the remaining pressure may exist in the hydraulic hose which need to replace, when unscrew the nut of the connector, the hydraulic fluid perhaps splash out, in order to avoid that, it is neccessary to relieve the pressure of the hydraulic system.
Take off the hose sleeves if it has:
If the hose sleeves exist, you should take them off, it will contribute to the convinience to operate.
Unscrew the connectors of the two end one by one:
When all the preparation is ok, unscrew the nuts of the hydraulic connectors on the two ends, note that, unscrew the gradually to check if there is remaining pressure in it, wipe off the dirt or the oil if neccessary in order to contamination can’t enter the hydraulic system.
Screw the new hydraulic hose with wrench:
Before screwing the new hoses, you should wipe off the dirt and contamination around the connectors, and then screw the two connectors one by one with wrench, stop rotating when the connector doesn’t spin any further.
Put on the wraps or the sleeves of the hydraulic hose:
Refer to the photos you took just now, put on all the wraps and sleeves you jut got off to prevent the hose from rubbing any other elements.
Test the system bu circulating the hydraulic fluid at low temperature:
Run the machine and set the hydraulic mechnism to low power, and check the hoses for leaks by sliding a piece of cardboard around it.
If you hear air escaping or see the carboard is oiled, they shows leakage exists, and then turn off the machine, double check the connectors and tighten them again, if leakage takes place on the hose, then repeat the up step the change a new one. continue with the same procedure until there is no leakage.
In normal conditions, the lifetime of a hydraulic hose is from one or two years to five years, it depends on your frequency that put into use and the ambient environment, however, periodical inspection is necessary, after all, it is easy to imagine the results which the broken hydraulic hose bring out.
Hydraulic hose replacement needs some professional expertise and experience, but if you following the guidance above and work with that carefully, you will make it.
Sinopulse Group is a professional hydraulic manufacturer of China, We supply a wide range of rubber hoses that adhere to SAE and EN standards, and for industrial use, we have been a reliable rubber hose supplier of many clients all over the world.
If you have any questions, don’t hesitate to contact us.