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MG Midget and Sprite Technical - Fuel Tank sender gasket cement

I have just dropped the tank on my 71 midget to locate the recent fuel leak having filled it to the brim prior to a scenic run. It was from the rubber seal between the fuel sender and tank - it is the 6 hole type with a metal retaining ring above the unit.

Haynes mentions ‘suitable gasket cement’ – there is no evidence of any one there which might be part of the problem. Do I use RTV?

Also , there are no rubber strips there – I take it I need 2 long ones but how many of the short ones do I needs and where do they go?

Thanks

Mike
Mike Dixon

Mike,
I don't know about the cement but you need two short, they're not really strips more rubber gaskets to the captive screw threads, one each front and rear of the tank. The long strips go over the two, each side, captive screw threads at the sides of the tank (hope that all makes sense).
Nigel Atkins

The Moss catalog (can be viewed online) shows the strips. I've just fitted them to mine, I bought some but you might as well just cut them out of a sheet of rubber or similar.

As for the sealant I don't know, I didn't use any, just a new rubber seal. Hopefully it won't leak first time I fill it up!
John Payne

The strips are there just to isolate the fuel tank from the ribs of the boot floor. It stops damage from the two surfaces rubbing against each other.
I just cut them out of some 2mm thick cork floor tiles that I had. Fastened to the top of the raised ribs on the tank with a bit of double sided tape
GuyW

Thanks. I gather the sender gasket is cork- the one I have take off is rubber and has deformed and split. I will fit it dry and tape on the rubber strips to the ribs.

Mike
Mike Dixon

Thanks - gasket fitted dry and it is fine - duly tested before fitting. I got the rubber strips at the same time for about £3. The gearbox is my next thread.....

Mike
Mike Dixon

And just for future reference: Silicone RTV is not appropriate on fuel components, it eventually softens and breaks down.

Hylomar blue is the stuff you want.
Growler

Arend Stolte recognized the problem with the sender gasket and ethanol. As he was the former CEO of a rubber firm he could make an ethanol resistant gasket. Von Munching import is the only one I know who sells E 95/98 E5 resistant rubber gaskets. I use it for 4-5 years now and so far no problems. Before this gasket I have tried, without succes, everything described in this thread.

http://www.vonmunching.nl
info at vonmunching.nl


Flip Brühl

I have a leak which I noticed when I jacked up the rear of the car with a full tank. I suspect the sender gasket although I guess it could be the filler tube to tank. It's a 67 so I have bought a cork gasket ready to tackle the job when I get the fuel levdel down far enough. Would hylomar blue be best to use or just dry gasket?
Graeme Williams

I used blue hylomar when I did mine 10 years ago and no leak to date
Bob Beaumont

Did mine dry and no issues - I tried it with a bit of fuel in and tested it upside down swilling the fuel about and have subsequently filled it brim full - not leaks so far.

Mike Dixon

Dropped my tank just now to find the source of the petrol smell.

The last time I had my tank out, I too used blue hylomar for the sender unit and gasket seal. Never been a problem before. That was about 4 years ago.

Hylomar no longer resists petrol indefnitely. It had disolved quite a bit, fumes seeping past. Is it the E5 causing it, as it's now in even the esso 99 which I use?

Anyway, what to use now? I'm going to try pu sealant. Found quite a few posts says it works.

I've just dropped a cured lump of pu sealant into a jar with petrol. I'll see what happens to it.






anamnesis

Cured pu been soaking in fresh petrol for an hour now. No effect.

I'll whack it on as a sealant for my sender in a while and see what happens.
anamnesis

This is interesting. I've used and trusted Blue Hylomar for decades, including on fuel gaskets. Never had a problem. Not once.
But I'll be more cautious now.
I can only imagine it's the bloody ethanol.
Greybeard

Have never used gasket cement on fuel stuff. If i ever had a gasket leak just a smear of the old slimey soap works a treat.
In the old days at the races if we had a fuel leak in the tank ,it'd be jack it up to a position where it wasn't leaking and dry it off and push some wick in loctite in the crack, wait 10mins and off to the next race.
William Revit

This thread was discussed between 14/04/2019 and 16/06/2024

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