Jump to content

Tips for cleaning hydraulic hoses


Featured Posts

I once had a customer put engine oil in his brake master cylinder by mistake, Rover 2000. All the seals swoll up and jamed the brakes on. I had to renew every hydraulic seal in the system.  Dunlop calipers, Girling master cylinder, Lockheed servo, plus hoses. I bled and flushed it through with methylated spirit.

Link to comment
Share on other sites

I think the major danger will be from particles, not oily contamination. AS you can/could get oil that is suitable for both engines and hydraulic farm machinery I would have thought a lint free pull through and engine or hydraulic oil would remove particles. Otherwise fit the hose at the inlet and, put HOLD the other end in a drum and spin the engine on the starter in the relevant "gear". That should also flush it through. All suposing that you use a conventional hydraulic machinery oil

Link to comment
Share on other sites

I used to work for a hose manufacturer producing hoses for the rail industry. 

If they arrived without end covers send them back, ask for your money to be returned and go to a reputable supplier who will fit end covers as a matter of course.

If the supplier says they are ok to use tell him without covers they are unfit for purpose. Do not try to clean them before returning them. If he offers to replace them mark them in an unobtrusive way so you may recognize them should he send them back with end caps.

John

 

Link to comment
Share on other sites

As I mentioned above, we always used methylated spirit to flush vehicle hydraulic brake and clutch systems through, or the fancy name for it''denatured alcohol''. The internals of vehicle brake hoses are probably of very similar material as the hydraulic hoses, so I don't really see why it can't be used, but check with the makers.

Link to comment
Share on other sites

6 hours ago, John Hartley said:

I used to work for a hose manufacturer producing hoses for the rail industry. 

If they arrived without end covers send them back, ask for your money to be returned and go to a reputable supplier who will fit end covers as a matter of course.

If the supplier says they are ok to use tell him without covers they are unfit for purpose. Do not try to clean them before returning them. If he offers to replace them mark them in an unobtrusive way so you may recognize them should he send them back with end caps.

 

I used to work in the labs for BTR / Dunlop hose in failure analysis.  Having seen every possible way hydraulic hoses can fail in service, I agree 100% with the above.  

Link to comment
Share on other sites

I thought it was recommended to flush all hydraulic hoses before use regardless of whether they are caps as you can get rubber and steel fragments in the hose when they are cut and the ends terminated. hopefully the supplier would flush them before dispatch otherwise they require oil of the same standard that they are being used with pumping through them.

Link to comment
Share on other sites

6 minutes ago, Mike Adams said:

Mine  don't appear to have any damage either by chaffing or UV so why do they need to be replaced? I can see if they are exposed to UV on some piece of equipment or being moved often then that would be required.

I expect its in case of frictional wear inside the hoses caused by the hydraulic oil rushing round. Unlike vehicle systems where the fluid remains more or less static in the hoses.

Edited by bizzard
Link to comment
Share on other sites

10 years can be a long time for a hydraulic hose if the oil temperature is over 70 deg C . Hoses commonly fail next to the swaged end as the rubber slowly degrades until a surge in pressure, often when the oil is cold , causes failure. 

To flush fit the hoses at the pump end with the motor end securely anchored in a suitable container.  Run oil through both hose to the container, making sure you do not run the system dry. Discard this oil and connect hoses at the motor. Ideally you should be changing the hydraulic oil annually as well as any filter in the system.

The new hoses should be the better quality spiral wrap construction not cheap 2 wire (marked 2W )particulary if the pressure can exceed 140 bar. Industrial hoses often meet this spec, but this incurres a higher cost.

Link to comment
Share on other sites

The only information I have is that the burst pressure of the hoses should be more than 11,000 psi. The ones I have purchased are rated at working pressure of  215 bar or 3110psi with a burst pressure of 13,000 psi so I hope these will be fine. They are marked as ISO 1436 SAE 100R2AT the same as the old ones. I have yet to fit a pressure gauge to find out what the actual running pressure is but the bent axis pump and motor are rated at 420 bar continuous. I suspect the relief valve operates way below that though.

Link to comment
Share on other sites

On 16/12/2018 at 16:53, John Hartley said:

I used to work for a hose manufacturer producing hoses for the rail industry. 

If they arrived without end covers send them back, ask for your money to be returned and go to a reputable supplier who will fit end covers as a matter of course.

If the supplier says they are ok to use tell him without covers they are unfit for purpose. Do not try to clean them before returning them. If he offers to replace them mark them in an unobtrusive way so you may recognize them should he send them back with end caps.

John

 

Absolutely. I'm amazed at hydraulic hoses being supplied in this way.  Return required - but note that last line! This supplier clearly doesn't understand hydraulic hygiene - I'd go elsewhere. 

 

Those wondering whether there's good reason to replace hydraulic hoses which look perfectly OK and haven't been exposed to damage or uv exposure, etc, might wish to be aware that an hydraulic fluid leak under the sorts of pressure's referred to can produce an oil mist which, when combined with oxygen in the atmosphere, can be an explosive mix. Don't neglect the specified change intervals.  :)

 

On 16/12/2018 at 16:53, John Hartley said:

I used to work for a hose manufacturer producing hoses for the rail industry. 

If they arrived without end covers send them back, ask for your money to be returned and go to a reputable supplier who will fit end covers as a matter of course.

If the supplier says they are ok to use tell him without covers they are unfit for purpose. Do not try to clean them before returning them. If he offers to replace them mark them in an unobtrusive way so you may recognize them should he send them back with end caps.

John

 

Absolutely. I'm amazed at hydraulic hoses being supplied in this way.  Return required - but note that last line! This supplier clearly doesn't understand hydraulic hygiene - I'd go elsewhere. 

 

Those wondering whether there's good reason to replace hydraulic hoses which look perfectly OK and haven't been exposed to damage or uv exposure, etc, might wish to be aware that an hydraulic fluid leak under the sorts of pressure's referred to can produce an oil mist which, when combined with oxygen in the atmosphere, can be an explosive mix. Don't neglect the specified change intervals.  :)

 

Link to comment
Share on other sites

9 hours ago, Sea Dog said:

Those wondering whether there's good reason to replace hydraulic hoses which look perfectly OK and haven't been exposed to damage or uv exposure, etc, might wish to be aware that an hydraulic fluid leak under the sorts of pressure's referred to can produce an oil mist which, when combined with oxygen in the atmosphere, can be an explosive mix. Don't neglect the specified change intervals.  :)

 

and also if you ever suffer a burst hose inside the boat the cleaning up will make you much more mindful of hoses - says he who had to clean up a back cabin on a Broads cruiser when a hose chaffed through.

Link to comment
Share on other sites

10 hours ago, Tony Brooks said:

and also if you ever suffer a burst hose inside the boat the cleaning up will make you much more mindful of hoses - says he who had to clean up a back cabin on a Broads cruiser when a hose chaffed through.

True, and you could certainly do without that - I'll bet everything looked nice and shiny though, eh? :D

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.