JeffHs
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| posted on 26/1/09 at 02:38 PM |
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Help - Hydraulic seal material
Hi
I'm on another search for unobtainium, the final bits for the Auster (to repair the hydraulic flap actuator).
I need to source small cup seals like the ones found in brake cylinders, but they must be compatible with mineral oil.
Our local seal specialist came up with an alternative design but it failed.
I believe, but I may be wrong, that seals designed for DOT4 fluid are no good with mineral oil. Is that right?
Standard hydraulic stuff like O rings are made from Viton. What do they make brake rubbers from?
Jeff
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MikeCapon
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| posted on 26/1/09 at 02:45 PM |
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Your'e right. The compatibility of various seal materails with different liquids and gases is quite a minefield.
Standard O rings are made from Nitrile rubber, usually NBR70 (70 is the hardness in shore). These should be OK for ordinary mineral oil.
Viton seals are much rarer and more expensive. They will resist higher temps (200°C as opposed to around 100°C for nitrile) but the resistance to
tearing is much poorer than nitrile.
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paulf
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| posted on 26/1/09 at 02:45 PM |
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I think the seals used for mineral oils are nitrile rubber or viton as in O rings etc.Not sure what spec car brake seals are although I do know the
Citroens with hydraulic suspension used mineral oil in the suspension and brakes, old Rolls cars also used a hydraulic system with mineral oil if I
remember correctly.
Paul
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pewe
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| posted on 26/1/09 at 02:50 PM |
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Found these guys on my database but don't know if they can help - may know someone who can.
HTH.
Cheers, Pewe
Del Fastenings and Fixings
Fastening & Fixings, Sheet Rubber
Gaskets & Seals
Unit 9, Elvetham Bridge, Fleet, Hampshire, GU51 1AE
Tel: 01252 626425 / 627229
Fax: 01252 811741
Email: info@delindustrial.co.uk
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02GF74
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| posted on 26/1/09 at 03:36 PM |
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quote:
Originally posted by JeffHs
Our local seal specialist came up with an alternative design but it failed.
what exactly do you mean by that? The parts were different design i.e. shape/size or of different material?
In what mode did the parts fail?
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g.gilo
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| posted on 26/1/09 at 04:18 PM |
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seals
hi
construction equipment , diggers dumpers etc use brakes enclosed in the axle,similar to a bike clutch.
because the axles are filled with mineral oil so are the brake systems.
try twaites at leamington spa or terex at warwick, or a good plant hire company.
graham
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JeffHs
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| posted on 26/1/09 at 05:00 PM |
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re failure.
Instead of a cup seal he proposed a 2 part seal where one part was installed inside the other using a cone. Sorry I'm a bit vague on the detail.
I'm picking this up where someone else left it.
The seal did not hold pressure.
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