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SU pump diaphragm

Posted: Sun Jan 15, 2023 7:50 pm
by alanworland
My 1952 MM still has the original SU pump diaphragm which has never given any problems.
I bought a spare diaphragm probably 10/13 years ago but with the addition of ethanol to the fuel I should really purchase and fit suitably resistant one.
Any recommendations for a supplier?

Alan

Re: SU pump diaphragm

Posted: Sun Jan 15, 2023 8:54 pm
by svenedin
You can buy directly from Burlen fuel systems. A full service kit is not much more expensive than the diaphragm alone and you will need new gaskets anyway. It is not a particularly difficult job but a bit fiddly. There is a guide to overhauling an SU LP fuel pump on here (partly written by me). When setting the throw of the diaphragm (which is achieved by screwing it all the way in and then unscrewing) you do need to connect the pump up to 12v and test it and adjust until it is working correctly before tightening everything down. A spare battery or 12v bench source is useful for this but you can do it using the car battery (just more fiddly). This is a good opportunity to give the pump a thorough clean out. Carburettor cleaner works well. https://sucarb.co.uk/su-fuel-pumps-spar ... -1985.html

Stephen

Re: SU pump diaphragm

Posted: Mon Jan 16, 2023 4:20 pm
by alanworland
Thanks for that never thought of Burlen! That's suitable for my original pump - not done bad for 70 years!

Alan

Re: SU pump diaphragm

Posted: Mon Jan 16, 2023 7:31 pm
by geoberni
Equally, don't forget that Ethanol has been in fuel since these cars were first made, it just wasn't made a big deal of.
Well apart from Cleveland Discol adverts.... :wink: https://www.youtube.com/watch?v=4uEqqlqqf4Q

Re: SU pump diaphragm

Posted: Tue Jan 17, 2023 6:01 pm
by James k
I used this video to rebuild mine and it was all really easy.

https://youtu.be/oU5uLjuOQdM