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small gas leak around sender unit at on gas tank

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Drew1957 Stephen S
Caledon, ON, Canada   CAN

I noticed that I have a small gas leak around the send unit on the gas tank. Is there something I could apply to this area that might stop it? Or open to any othe suggestion?


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Gary E Avatar
Gary E Silver Member Gary Edwards
Kernersville, ,N.C., USA   USA
I have found that the only way to seal it was to remove the sender and start over. Use a new cork gasket and Hylomar gas resistant sealer. Some say no sealer is needed but they are better at this than me...


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Cusailer Avatar
Cusailer Philip Gable
Urbana, IL, USA   USA
1980 MG MGB
I would drain the tank, remove the sending unit and replace with a new gasket. It isn't that difficult and can be done without raising the car. I've always used rubber gaskets. Nothing lasts forever, but at my stage of life something that lasts another 30 years should do it. smiling smiley

I've never been a fan of quick and easy fixes because they always seem to take more time and cost more $ in the long run. Removing the sender is easy unless it is really rusted. If the sender is rusted too badly, I would think about replacing the tank since it too is likely rusted on the inside an pushing crud to your filter/carb. Good luck!

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Redhawk1689 Avatar
Redhawk1689 Gold Member Steven Stockham
Salina, KS, USA   USA
1958 MG MGA 1500 "Belle"
I'm going to concur with the others. I had a small leak that happened because I originally had the sending unit in upside down and tried to re-use the gasket. I had to get a new gasket (cork) and start over (oh yes, I had to drain the tank even though it is brand new.) Now, the leak is stopped. Save yourself a lot of aggravation and don't do half-measures!

Gary E Avatar
Gary E Silver Member Gary Edwards
Kernersville, ,N.C., USA   USA
Go to your Harbor Freight type of store and get a cheap syphon pump.. Easier than draining into a tub..


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A on a shoe string Avatar
A on a shoe string Peter Stevenson
Aubusson d'Auvergne, Auvergne, France   FRA
1960 MG MGA 1600 "A"
1972 MG Midget MkIII "Midget"
Depending on how much of a fix you're in... and the size of the leak, rubbing a bar of soap on the leak is a good 'get you home' tip. Had a friend hep me out with such a problem after knocking a fuel line on a rock, Couldn't believe how effective it was.

Good luck. Pete

3066james Avatar
3066james Gold Member Jim Cheatham
Amelia, VA, USA   USA
I agree with others that you need to take it out and start over. You don’t have to empty the tank but you do have to take enough gas out so when you jack up the right side of the car, gas won’t leak out of the sending unit hole. Make sure you disconnect the battery.

I used Seal All on the cork gasket and gas resistant Teflon tape on the threads of all of the screws. I also took the small rectangular cover plate off and put some Seal All on the threaded rod that goes through bottom of the unit to keep gas from leaking through there.

All of this was my second try since my first try leaked just like you have experienced.


Edited 1 time(s). Last edit at 2018-01-05 09:14 AM by 3066james.

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Rob Z Avatar
Rob Z Silver Member Rob Zucca
Camarillo, CA, USA   USA
1960 MG MGA
Correct as Jim says. You don’t have to drain the tank all the way. Half should do it and jack up the right side of the car. Take out the bottom screw first. If fuel drips out, put it back and drain a bit more until the level is below the bottom most screw. I use the OEM cork gasket also, but do put a little fuel proof sealant on the screw threads. Some of the holes in the gaskets are a bit too large for the screws allowing leakage. You can also easily make a new gasket using sheet cork gasket material from any auto parts store and punch the screw hole smaller than the screw threads. This will allow the cork to squeeze tightly against the threads. In this case you probably wouldn’t need any sealant.

"Time flies like an arrow......Fruit flies like a banana"

Redhawk1689 Avatar
Redhawk1689 Gold Member Steven Stockham
Salina, KS, USA   USA
1958 MG MGA 1500 "Belle"
Yep, I should have added that! I didn't drain the tank entirely either!

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yovinny Avatar
yovinny Silver Member Vinny Minchillo
Plano, TX, USA   USA
1962 MG MGA
And don't be shocked if you do all this and it still leaks. I tinkered and tinkered tightening and loosening screws until I came up with the secret combination that kept it from leaking. Spoiler alert: tightening them all really firmly doesn't seem to work.

Also, I used a rubber gasket and sealer.


1962 MGA
Plano, Texas

Graham MV Graham Martin
London, london, UK   GBR
All said above, but when I did it, instead of using a cork gasket, I sourced the more chunky rubber gasket, that allows for imperfections in the tank surface.
I used Hylomar Blue (including on screw threads) but go very easy on it. I have heard of excess falling in the tank and clogging up the system!

Good luck

Twofin Avatar
Twofin David T
Bedworth, Warwickshire, UK   GBR
Hi, above post here in the U.K. To address this problem we fit the Edney Viton rubber seal it is also shaped rather Than flat.
Just Google Dave Edney MG

copernicus Avatar
copernicus Nick Kopernik
I too had multiple issues with leakage after I replaced by fuel tank many years ago. The cork product just would not work, even with sealant. I spent a bit of time searching and found a product made here in CT which solved the problem on the first attempt. Its called Appopac and it combines cellulose fibers and synthetics to provide a perfect seal. Product has the feel and texture of leather but looks like kraft paper and is approx 1/16" thick. At that time the manufacturer did not sell directly to the public, but they were kind enough to give me a number of leftover pieces large enough for me to cut my own fuel sender gasket. I checked out their website and it seems that they may have changed their policy on direct sales:

As an added treat, I stopped by F40, which was just a few miles from Auburn Mfg. Lots of nice cars on display, but Wayne Carini was not there that day:

bikermga Avatar
bikermga Peter Tilbury
Surrey, BC, Canada   CAN
The VITON sender gasket from Scarborough Faire does not leak.

Also, Permatex now make an equivalent to Universal Blue Hylomar. It is their product number 85420. Not many places stock it. I had to order from O'Reillys but they had it a day later. it stays flexible, and does not harden. It is resistant to all fuels. It costs about $10 for a 2 fl oz (59ml) tube. I have been using this for about 8 months on engine rebuilds etc and it is great.


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