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'69 leaking gas at sending unit

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Old Apr 15, 2019 | 08:57 PM
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Default '69 leaking gas at sending unit

Hello all. Just the other day I decided to fill the gas tank up because it had been siting in my garage with a 1/4 tank for a few weeks. The next day I discovered that my gas had just started leaking out from above the spare tire holder. I knew it had to be the sending unit. After removing the spare I noticed that it was in fact leaking from the sending unit. If I play with the nozzle it starts to leak a lot more. It seams to me like it was a little lose. I then drained the tank and checked the retaining ring. I was able to remove it without any tools telling me that that was the source of my leaking issue. After removing the unit, I inspected the rubber sending unit gasket. It looked fine to me which was no surprise because the entire unit was replaced about 4 years ago. Any ideas as to why it would be loose at this point? I'm ordering a new gasket but I'm worried the same thing is going to end up happening.

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Old Apr 15, 2019 | 10:07 PM
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From: Loud, Raw and Dangerous 1968 327 4S in Southern California
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Had the same thing happen to me recently...ended up tightening it and the leak stopped. Some possible ideas...vibration, ethanol gas affecting the gasket or original install not fully tight. I will also be interested in any other ideas.

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Old Apr 15, 2019 | 10:31 PM
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Originally Posted by Redvette2
Had the same thing happen to me recently...ended up tightening it and the leak stopped. Some possible ideas...vibration, ethanol gas affecting the gasket or original install not fully tight. I will also be interested in any other ideas.

Redvette2
The retaining ring was as tight as it could go. It slips into place and you just turn it like a 1/2" and it locks in place. It was in that locked position but it felt like if the gasket itself should have been make thicker. Had it been thicker I feel it would have pushed more on the retaining ring, thus forming a tighter seal. Unless it just shrinks in time I don't see how it never leaked before. Has anyone else had these replacement ring gaskets go bad so quickly?
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Old Apr 16, 2019 | 05:10 AM
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I have ! From brand new (O ring) I too had it rotated as tight as it went . What I noticed is that as it turned, it went a little off centre as well( the sender unit ) , I ended up using a screw driver to tap it back to central position which stopped the leak for me.

Last edited by bazza77; Apr 16, 2019 at 05:11 AM.
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Old Apr 16, 2019 | 09:02 AM
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Originally Posted by bazza77
I have ! From brand new (O ring) I too had it rotated as tight as it went . What I noticed is that as it turned, it went a little off centre as well( the sender unit ) , I ended up using a screw driver to tap it back to central position which stopped the leak for me.
Thanks bazza77. I'll be sure to look for this happening when I go to put my new one in.
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Old Apr 16, 2019 | 11:43 AM
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When I replaced my tank I also replaced the sending unit. Both parts came with the O ring but there was a minor difference in the thickness of the O ring. I went with the thicker ring that came with the tank.
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Old Apr 16, 2019 | 11:10 PM
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Originally Posted by MelWff
When I replaced my tank I also replaced the sending unit. Both parts came with the O ring but there was a minor difference in the thickness of the O ring. I went with the thicker ring that came with the tank.

See. This is exactly what I was worried about. Companies making different thickness O-rings.
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