Slow drip from gas tank drain plug...

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TechMOGogy
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Slow drip from gas tank drain plug...

Post by TechMOGogy »

So I have a very slow drip from the gas tank drain plug.
I managed to remove the plug and reanneal the copper washer, then smoothed it out with 600 grit sand paper on glass so it was super flat - still drips!
Off to the store and got their last two 22mm ID copper crush washers (900.4230) - yippie - installed one and it still drips. :evil:
The plug threads in and out easily so no issues there.
Should I try 2 crush washers?
Some sort of thread seal plus the crush washer?
Any thoughts or tricks I am missing here?
Thx
Dan
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker
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pcolette
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Re: Slow drip from gas tank drain plug...

Post by pcolette »

Hi Dan,
I developed the same problem after removing the tank to install a new pick-up tube. About 1 drop every 2-3 days. Tried a new crush washer to no effect. I was nervous about wrenching it too much and maybe cracking the weld so I just left it. Now (about 3 months later) it doesn't drip any more. Good karma maybe?

I'd try some thread sealing tape or a fibre washer on the plug.

Paul
Paul C.
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'73 Swiss 710M
'89 Puch 230GE
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TechMOGogy
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Re: Slow drip from gas tank drain plug...

Post by TechMOGogy »

I did it again (3rd times a charm) used a new crush washer and some aviation sealant and I think it finally got it!
Fingers crossed - will verify in the morning
Thanks Paul
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker
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rmel
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Re: Slow drip from gas tank drain plug...

Post by rmel »

Hmmmm, gas is a decent solvent :? that leak might develop again :(

If it does try cranking in that plug finger tight without a washer and see
if you can detect a valley point around the circumference of the seat on
either the plug or tank side, e.g. a gap. If you can get a 2 or 3 mil feeler
gauge in there at any point that would take some crushing to close.

As you apply force to crush you don't want to "stop" then tighten more as
then the copper stops flowing and takes a harness. A torque wench would
take the guess work out of it but the torque for these plugs is not spec'd in
the Manual.

I have shied away from using Aluminum washers on fuel systems, but they
are pretty common for high pressure AN fuel fittings. Might give that a try if
the problem persists.
Puller: 71' 710K 2.7L EFI aka Mozo
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Garrycol
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Re: Slow drip from gas tank drain plug...

Post by Garrycol »

I just put some petrol compatible sealant on the threads and use the recommended washers and never had an issue.
1973 Haflinger AP700
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1957 Landrover 88" Station Wagon
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TechMOGogy
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Re: Slow drip from gas tank drain plug...

Post by TechMOGogy »

The Permatex #3 aviation sealant is fuel resistant so we shall see.
On the plus side, I am now an expert at removing the plug with basically a full tank of gas (and Andre's tank guard that makes it a bit harder). :mrgreen:
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker
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rmel
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Re: Slow drip from gas tank drain plug...

Post by rmel »

Curious how you pull that plug on a full tank without getting a gasoline shower :roll:
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712MK

Driver: Ron // KO0Q
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Jack Russell Racing
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Re: Slow drip from gas tank drain plug...

Post by Jack Russell Racing »

rmel wrote:Curious how you pull that plug on a full tank without getting a gasoline shower :roll:

Well obviously he flips the truck upside down!
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TechMOGogy
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Re: Slow drip from gas tank drain plug...

Post by TechMOGogy »

Jack Russell Racing wrote:
rmel wrote:Curious how you pull that plug on a full tank without getting a gasoline shower :roll:

Well obviously he flips the truck upside down!
Dam! Never thought of that!! :mrgreen:

Basically it was a fast game of 1 finger Lucy... plug out and finger in.
As always, the first time was not fun, but by 2nd and 3rd I lost less than a cup or two.
Hopefully, I don't have to do that again and if for some reason I do the tank will be near empty and I will just drain it.
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker
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audiocontr
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Re: Slow drip from gas tank drain plug...

Post by audiocontr »

Can you place a plastic bag between the cap and the filler tube to limit the amount of liquid which pours out?
1973 712m
1968 Haflinger
1965 Pathfinder
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