Gas tank question

The drain plug in the bottom of the gas tank on my 55 Savoy is leaking and the gasket is all busted up. What material should I use to make a new one.

copper or aluminum sealing washer

is it a pipe thread or regular thread ?

Pipe thread wouldn't use a gasket.

that's what had me stumped. the tanks i've seen that had a drain usually had a bung that was pipe thread. if it is the common 1/2x20 thread, a gasketed replacement oil pan drain plug would be an easy fix. i have those with a copper gasket, as well as several that have an o-ring washer deal.

Problem is compatibility. Some rubber falls apart in the presence of gasoline. I have no idea what those oil pan drain plug gaskets use.

your copper/aluminum gasket ring would be the best fix, and relatively easy to procure.

I used a rubber O ring on my '56, don't remember the size but the slight recess in the tank skin made the O ring compress without oozing out the side of the plug.

Sorry been out at an estate sale picked up a few items. I found some copper crush washers in the Mcmaster carr book at work yesterday. Just gotta measure the plug and get some that fit. Picked up some hub caps for an old dodge and a old sun timing light that still works. It's a 1953 model and is 6/12 volt.

let us know what thread size that turns out to be. i'm curious. i have a plymouth cap similar to your last pic, only in worse condition, hanging in the garage ! the timing light is a nice score !

OK, I have a '56 Plymouth (wagon) that I am changing to fuel injection, the old original tank has not had fuel in it for many years. I took the plug out today to see what kind of gasket was used. I used a 1/2 drive extension for the double hex plug. NO gasket, I am sure there is supposed to be one, it just had disintegrated. The OD of the threads is 7/8 inches. I think any nylon or copper gasket would work.

I should have the tank back this week I took it to have it cleaned up and checked out for any other leaks. That's my plan for the old Plymouth hub cap is to hang it in the garage.