'59 Plymouth Forum

Just an after thought....if tarpaper is to be used, why not use ice/snow paper instead. It is a tad thicker than 15# or 30# tarpaper and IMO the benefit would be that one side has an adhesive layer. I might add, a very good adhesive.

So if this material is stuck to the tank, maybe no moisture could get between the two surfaces like it possibly could with plain 'ol tarpaper. Smallest roll, I think you can get is 3' wide by 33' long, so a friendly roofer might be the ticket.
The purpose of the adhesive is to prevent water from getting to your roof sheathing, so same theory should work on tank.

I far as I'm aware it's a 20 gallon tank on the car and 22 gallon for the Suburban. These repro tanks are 22 gallon but once fitted don't look much different to the factory fitted.

Using a bitumen based material for the pad shouldn't give any issues as it's impervious to water and it seals to the contours of the tank. If you were to use an "open cell" foam type pad then you' be asking for trouble as that would soak up the water.

As extra insurance I got it painted with underseal to further protect against the elements. It should see me out cos' the last one seemed to be okay for 50+ years.

My only concern is the make up of fuel has changed. In the UK we typically have 5% ethanol and possibly a methanol mix in the future. You've had ethanol in the US for some time, do you have to guard against this with steel tanks. My understanding is that any water collecting in the tank will mix with the ethanol and lead to formulation of aggressive corrosive substances. Any chemists out there ?

Guy