Well the tank in my 77 crewcab is a leaker and im obviously going to have to fix it. This is the in cab tank. Im not interested in
Trying to install a frame mounted unit due to exhaust and drive shaft and crossmember concerns

So im going to have to oull and reseal the tank, who's used what and how did it hold up?

I’m 15 years on a 70 Cuda tank that I sealed with “U.S. Tank Sealer”...the brand that was sold through POR15 years ago. It’s was considered the ‘go-to’ brand back then, I don’t know what the market is like today.

It’s held up just fine.

I used the kit Eastwood has (had?) on the tank in my wagon w-a-y back about 2001? Tank had some very slight pinholes in its bottom (and NO ONE makes a repro tank for a wagon).

It lasted until about 2017? but I blame myself more than the product. By 2017 the wagon was basically just sitting, and the couple of gallons of gas in the tank had gone bad. One of the pinholes started leaking again.

I think if I had kept fresh gas in it, it would have been fine.

So, I got over 15 yrs of use with NO issues.

EDIT: just took a look, they still have the kit I used. >>>> eastwood gas tank sealer

With a metal tank you can solder a patch on it. Where is it leaking? I don't ever think I have seen an in cab leak unless punctured or rubbed through.

Tank in my 65 was really nasty and terrible.Used the POR15 kit in it like 25 years ago.Installed new sender about 10 years ago and it still looked like new.I did let the cleaner set in the sun a day Then after I flushed it and installed the sealer I let it sit like a dy or two in the sun.I did have a small pin hole in one corner I solderd it when the tank was out before I sealed it.Used on sealer in my Harley tank years ago.It starting coming off and was like gum.Used POR in it also and no problems..Rocky

So seems like good results with Eastwood and Por15. Looks like ill be ordering one of those.

As for why rusted? The truck sat for a very long time, who knows how much gas was in it, how much water etc.
It rusted from the inside. Im pretty sure theres about 2 inches of rust flakes in the bottom of it, i know the pickup tube is way short of reaching the bottom.

I don't expect to find a big hole but probably a few pinholes. More after cleaning it out.

Definitely POR-15's "US Standard Tank Sealer". I've used it on several tanks,both diesel and gas, all of which have held up for 20 years (so far)

Every stop leak product I've read the fine print on says "don't use with ethanol blended fuels". My guess would be it dissolves them and ya end up with some amout of gunk somewhere in the fuel line. With a metal tank I'd absolutely patch it before trying to putty over it.

For concerns about soldering with an open flame: find a hunk of metal with a wood handle, use a torch to heat it, solder with that. A guy that did one of my tanks years back had one that looked like an oversized soldering pencil and no clue what it was actually supposed to be. Maybe try a fireplace poker or a branding iron.

Ive had ethanol mix in both my 65 and my Harley.Both POR15 and never any problems.The one sealer I used in my HD tank years ago made a gum like mess when they started using alcohol ingas.Both tanks I have are at least 20 years witPOR 15 and never a problem.Rocky

My son used a product that I thought was the POR-15 brand. After purging all fumes by filling the tank with hot soapy water for a day, we used 3 US Lincoln pennys to solder up the three pin-holes. This sealer went in the tank in a dark blue thick liquid. After coating all surfaces inside we poured the excess out. Then sat the tank in the sun for two days.

It does not leak. He had MIG welded a rear tank sump with two fuel line bungs. This was the reason to do the sealer and it has worked well. But even after a few years his pump gas fuel comes out blue in color.

Blue wasnt POr unless they changed it.IIRC mine is silver color.Gas never changes colors.Only problem I ever had was sealer I used in 80s.It got gummy and cloged my shut off.Never used it again.rocky

The US Tank Sealer I used around 2005 was grey. No problems

I vote for Red Kote. I have used it, the POR 15 product, and something called "KREEM" over the years. Never use the KREEM product again, it peeled in sheets from 2 different tanks.
One on an old Honduh CB 360 bike and one on a 12hp Kohler gas tank on a Cub Cadet.

The red kote says has no problem with ethanol, there is another type of fuel though it says "not to" use with, there is a number on the can to call if you want to use that sort of fuel.... I forget what type that was....but ethanol is no problem with it, I have used this stuff on a 1/2 dozen tanks now, no issues. They DO say though that your fuel may take on a red tinge, has no effect on the sealing properties of the product and will not hurt the rest of the fuel system either. I have used on several small engine/garden tractor tanks and so far so good... I think the company that makes it is called Damon Industries. This product has been around for many years.

volare Kreem was what I used in my harley tank years ago.I thought someone put something in my tak Was terrible.Plugged up the fuel lines etc.Used POR15 and no problems.Rocky

When I was first looking at tank sealers 20+ years ago, I found that Kreem did not have a good reputation (many stories like Rocky's). The "US Standard" (POR-15) kit works perfectly, if the instructions are followed to the letter. The most critical part is getting the tank bone dry after the cleaning. I tape a hair dryer to the necks of mine and let it run on low heat for several hours (out in the sun, too).

Dollar bills will fix your fuel tank problem

Why not find a good tank and install it?

Because 45 year old dodge trucks aren't really common around here.