Gas tank bungs leaking..., Any tricks to make them seal better? Options

[bigkensteele]

I pulled the tank and completely re-plumbed my fuel system, including new little red seals on the bungs at the bottom of the tank. Cleaned all the hardware thoroughly before re-assembly.

Now, the garage smells like a refinery.

Unfortunately, the bungs are leaking like crazy. Not quite dripping, but they are wet enough to be the obvious source of my leak.

Any tips on getting them sealed up properly? Is there only supposed to be one little red seal on each bung, or two?

[Mike Bellis]

I would use a copper washer to seal it. The seal sould be on the tank, between the tank threads and the nipple. The cap nut holds it on. I'm not sure what the "red seal" is. If it is a stock seal put it in the same place. There should be no seal between the cap nut and the nipple.

[bigkensteele]

I would use a copper washer to seal it. The seal sould be on the tank, between the tank threads and the nipple. The cap nut holds it on. I'm not sure what the "red seal" is. If it is a stock seal put it in the same place. There should be no seal between the cap nut and the nipple.

That is the manner in which I installed them, other than the copper washers. I bought SS lines from Rotary, along with a new sock and the seals. The seals look exactly like the old ones I removed, and I installed them between the nipple and the tank.

Any other ideas?

[Mike Bellis]

Go to harbor freight and buy the copper washer kit. An aluminum washer could be used too. It needs to crush to make the seal.

Turn the tank upside down and use a very fine wide file to flatten the sealing surface at the threads. You could also use some fine sand paper on a flat block (glass or steel). You need to keep it perfectly flat and 90 degrees to the bung. Worse come to worse, there are some fuel compatable sealants out there.

[bigkensteele]

Go to harbor freight and buy the copper washer kit. An aluminum washer could be used too. It needs to crush to make the seal.

Turn the tank upside down and use a very fine wide file to flatten the sealing surface at the threads. You could also use some fine sand paper on a flat block (glass or steel). You need to keep it perfectly flat and 90 degrees to the bung. Worse come to worse, there are some fuel compatable sealants out there.

Hmm. Didn't know HF sold a copper washer kit. I was planning on going there anyway tomorrow to get a siphon pump and a couple of tanks to extract all of the gas. I will look for the washer set, and perhaps some sealant. I don't want to do this again.

Thanks for the tips.

[mark21742]

If you can't get it to seal, just run down here to south Pa and grab my stock gas tank.....its here, its out, its good, and its free (IMG:style_emoticons/default/smile.gif)

[r_towle]

I have heard of others using AN fittings and tapping the inside of the bungs for the AN fitting.
Keeps it leak free.

Rich

[IronHillRestorations]

Lap the fittings together. Tighten the sleeve nut by hand and rotate the fitting back and forth 90* while you gradually tighten the sleeve nut, finishing with the fitting in the correct orientation. This has helped me with seeping AN fittings more than once.

[kconway]

If you want to use AN fittings check this out, no tapping.
https://secure.cbperformance.com/catalog.asp?ProductID=1709

[bigkensteele]

I ended up pulling the tank and filing the mating surface flat as Mike suggested. I also bought the copper washer kit from HF, and the 3/8" fit perfectly. I used Indian Head gasket sealant on the mating surfaces and put it all back together. So far, so good, but I am going to give it a while before I fill the tank. I have enough gas cans to hold about 5 gallons, so I won't run any more than that until I KNOW it is no longer leaking.

Thanks for all the suggestions.