Lotus Elan

Fuel pump leak

PostPost by: rtischler » Sun May 24, 2015 3:49 am

Hi all,
Just coming to the finishing stages of my first phase of restoration and I?ve run into a small fuel leak. My S2 elan is fitted with weber carburetors, new all metal style pump, canifure line from fuel tank to pump, and a braided stainless line connecting the fuel pump outlet to the carburetors. My leak is coming from the outlet and upon closer examination the copper pipe entering the outlet on the pump felt loose even with the nut quite snug.
Originally I installed the outlet fuel line with a small copper ferrule and after I noticed the leak and removed the line the ferrule didn?t appear compressed at all compared to images I?ve seen on this forum. I also tried to flare the copper tube hoping for a different result however the leak persisted and in a more serious state.
Honestly I have a very minimal knowledge of mechanical fuel pumps and I?m not sure how to narrow this down. Am I using the incorrect ferrule, nut, or both?? Would be interested in some of your experienced opinions.
I?ve attached some images for clarity..

Ferrule seen has been installed but doesn?t appear compressed at all to me?
Image
Fuel line to carbs
Image
What my fuel line & ferrule looked like immediately after uninstallation.
Image
View inside the fuel pump & outlet.
Image
Attempting to flare the fuel line.
Image
Rob
1965 Lotus Elan S2 26/4660
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PostPost by: HampshireMush » Sun May 24, 2015 10:06 am

I recently had a fuel leak on the inlet side of the fuel pump and it would not tighten any further so I replaced both inlet and outlet to be on the safe side. The job is a PITA as access is poor and I ended up taking the carbs (Strombergs) off - just as well as I found a fuel weep on the rear unit float chamber plug when it was off.

I used some 1/4" Cupro Nickel pipe and new olives and nuts and it was tight first time and no leaks since.

I do not think the flare will work as the connectot is not designed for that IMHO.

John
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PostPost by: dougal9887 » Sun May 24, 2015 8:19 pm

A key requirement of making a leak proof compression joint is getting sufficient pressure on the olive to grip the pipe tightly, and this can be tricky in a confined space. A copper olive can make the job much easier. Alternatively use a standard plumbing 8mm compression nut to set the olive on the pipe, it then only requires a nip up to seal.
20150524_185804.jpg and
8mm plumbing compression nut.

20150524_185823.jpg and
Using a nut to set the olive on the pipe.

Dougal.
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PostPost by: tischler » Mon May 25, 2015 12:46 am

Thanks for the response, I'm going to look into compressing the ferrule before installation.
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PostPost by: alan.barker » Mon May 25, 2015 7:17 am

Dougal you are 100% right.
Just make sure there is a little bit of pipe coming out olive, not too long for counterbore in pump
Alan
Alan.b Brittany 1972 elan sprint fhc Lagoon Blue 0460E
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PostPost by: tischler » Sun May 31, 2015 5:32 pm

I was able to successfully cure my leaky fuel pump. I tried to compress the ferrule on the bench but I couldn't find the correct cap for my brake line fitting. I ended up using a new ferrule and the job was done.
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