Leaky Petcock Questions

Dr. Frankenstein · Post by **Dr. Frankenstein** » Thu Apr 05, 2018 8:09 am

I recently had to re-drill the petcock holes on my CA95, and decided to replace it with a flat, round piece of aluminum, drilled and tapped to take a cheap fuel tap.

That works great, but fuel is managing to leak out from the tank and in between the cork gasket I'm using and ruing the paintjob.

Is there any good way to make sure an aftermarket (or fabricated, in this case) petcock won't leak? Gasket sealant, maybe? Although everything I've seen so far says to not use in direct contact with fuel...I'm thinking about JBWelding it; do I have any other options?

Tim Allman · Post by **Tim Allman** » Thu Apr 05, 2018 9:11 am

A photograph would be helpful.

Hahnda · Post by **Hahnda** » Thu Apr 05, 2018 12:46 pm

Are you using a flat wide gasket between the tank and your adapter plate? Sometimes a narrow gasket will work better as the pressure will be higher at the contact area. That might help to seal it better. If you could put some sort of groove in your plate and use an ring that may also work better.

mike in idaho · Post by **mike in idaho** » Thu Apr 05, 2018 8:52 pm

Any sealing washers under the mounting screw heads? Gas will migrate down the threads and appear to be coming from elsewhere.

Dr. Frankenstein · Post by **Dr. Frankenstein** » Fri Apr 06, 2018 5:41 am

Those are both good ideas - I don't think I tried using sealing washers before, but I will now.

I was using a rubberized cork material that covered the whole surface of the aluminum plate for the gasket between the tank and the fuel tap, with a liquid sealant on the screw threads; but thinking about it, a combination of the sealing washers and a narrow gasket might work - I have nothing to lose by trying, anyway.

And yes, when I was fabricating the aluminum discs I had them cut from the bar stock by a guy in a metal shop, but all he did was just cut the discs - 53mm wide by about a half-inch deep. Yes, I would like to have a circular pathway for a gasket routed in to the aluminum discs, but that might be kind of expensive - I found out machinists don't work cheap.

I tapped a hole in the middle for the fuel tap and drilled and tapped the screw holes, but (so far) it doesn't really seem to work - it drips a lot.

What are you guys using for a fuel tap, if not the original petcock? And how are you sealing it?

Geoff Hastings · Post by **Geoff Hastings** » Fri Apr 06, 2018 10:46 am

I did the same as you, I got fed up trying to keep the original tap from leaking so made up an aluminium disc and fitted a cheap tap. I used a piece of cardboard as a gasket and put fibre washers under the head of the screws and so far it's lasted a year with no problem.

Dr. Frankenstein · Post by **Dr. Frankenstein** » Fri Apr 06, 2018 2:22 pm

Good to know - what kind of cardboard? Like, regular shipping/box cardboard or thin cardboard, like you find in shirt packages, or...? Doesn't it get soaked with fuel?