1982 GS450 Gas is leaking through screws?

[System9]

1982 GS450tx
I bought this bike recently and had to refinish the inside of the gas tank, it was rusted. I did Aqua clean, rust blast, re-coated it over the period of a week. Yesterday I put the fuel petcock back on, put gas in it and gas appeared to be leaking right from the screw heads that attach the petcock? Now, i know maybe the gas was leaking from somewhere else, and just dripped from the screws, But after messing with the screws (re-tightening/swapping with one another) it seemed like more or less gas was coming from the screws directly. Has anyone had issues relating to gas leaking out of the screw holes? Can gas somehow slip past the threads of the screws, and if so, is there a remedy for this? I have already ordered replacement screws/bolts, washers and the rubber gasket, but was wondering if there is anything else relating to the screws or the screw holes that needs to be addressed, like a coating you put on the threads?

[tom203]

You'll probably want to buy the special washers that sit under the screws- they have a rubber gasket and this will stop gas from running down screw threads . Might as well get a new oval o-ring while you're at it.

[IanDMacDonald]

Leaky screws

Hey-

I swapped my petcock with another vacuum petcock from my Yammie, as I thought it was the petcock malfunctioning (it was not). Anyways, I had the same problem as you, and it turns out, it's not actually leaking from the screws, but the holes where you have the screws into. There is a possibility that the holes may have become bigger than the screws due to whatever. My problem was that the Yammie's petcock screw placement was maybe a 1/16 of an inch wider than the GS's placement, which offset the petcock by that much, thus the leakage.
I used a product called "Seal All" from Auto Zone. It comes in a yellow tube for a couple of bucks, and works as a gas sealant, etc. I literally caked it on the screw area and everything that made contact with the tank, and it works great! That is, if you do not mind the messy look, but. . . . who's looking under your tank anyways! It works great as a fix (temporary/permanent). Whatever floats your boat.

My suggestion would be to buy a new petcock, and see if that fixes the leak, if not, you buggered your screw holes, and wasted $40 on a new petcock that you will have to make ugly with Seal All.

EDIT: Tom below me got his in while I was typing. I did not have those special washers that I remember. Lol, I guess that will be the proper way of doing it!

[System9]

You'll probably want to buy the special washers that sit under the screws- they have a rubber gasket and this will stop gas from running down screw threads . Might as well get a new oval o-ring while you're at it.

Ok good, I did order a set of those, so I guess I'll just have to see if that was it. Thanks.

[System9]

Hey-
My suggestion would be to buy a new petcock, and see if that fixes the leak, if not, you buggered your screw holes, and wasted $40 on a new petcock that you will have to make ugly with Seal All.

I have a weird feeling I may have messed up the holes. The screws I put in don't look like the bolts I ordered as replacements. I think the previous owner may have used different screws, and while it wasnt leaking before I did the tank restoration, I'm thinking it may not have been leaking because there was a good amount of rust stopping up the holes.

[pete]

I have a weird feeling I may have messed up the holes. The screws I put in don't look like the bolts I ordered as replacements. I think the previous owner may have used different screws, and while it wasnt leaking before I did the tank restoration, I'm thinking it may not have been leaking because there was a good amount of rust stopping up the holes.

The PO may have screwed the threads up if he used different bolts to standard, so you may need to re-use those ones or find new ones the same thread.

You definitely want those washers in there though...

[System9]

I have the new parts on order, but i took it apart and did some investigating. The tank was "custom" painted, and the paint around the petcock area was making some bumps, so I chiseled and sanded down the mating surface, which i'm sure helped. Then after looking at the screws, I realized the holes on the petcock where the screws go through are purposely larger, otherwise the screws would never pass through. Its dependent on those special washers for sure. I did my own test using a rubber o-ring under a normal washer, and the leak completely stopped.