Gas tank pad?

[fireguyfire]

I’m just about to reinstall the fuel tank behind the seat after a full restoration of my 1970 d100.
I seem to recall during my tear down 2 years ago that there was a thin rubber pad (or pieces of one) under the bottom edge of the fiel tank where it meets the cab.
Is this correct? If so, what type of material should I use to make a new pad?

[PwrWgnDrvr]

Its not rubber. Very similar to 30# tarpaper, but that would melt away with a gas leak. Whatever it is, they are very brittle and break up after a few decades. Rubber also deteriorates quickly if contaminated with gas, oil, etc.

[fireguyfire]

Any suggestions on what to use to replace it?
Do you need to replace it at all?

[PwrWgnDrvr]

Probably dampens potential squeaks and/or wear-thru of the tank bottom. Neoprene rubber sheet is impervious to petroleum.

[Wildergarten]

Probably dampens potential squeaks and/or wear-thru of the tank bottom. Neoprene rubber sheet is impervious to petroleum.

Neoprene has very different friction characteristics than the impregnated fiber paper. One might wish to add a slip surface such as polyethylene in additional to an acoustical damping layer.

[martincom]

I've found rubber roofing, typically utilized on commercial flat roofs, to work well for a number of things. I originally began utilizing it when outfitting the aluminum body step vans we utilized in the business. I used it as a gasket between steel and aluminum components to prevent electrolysis. I also found it was far more durable than the front wheel house splash shield that came with the truck. The stuff is pretty tough and durable.

It is easy to work with. Lays out flat, conforms to contours to a degree. Accepts markings from a Flair pen. Cuts easy with a scissors.

I cut a piece of it to make a gasket for the filler neck extension on a cab I acquired for a John Deere 455 I use to own. Diesel fuel didn't bother it.

The stuff is cheap. When I go to the roofing contractor, they point me towards their dumpster.

[Wildergarten]

I've found rubber roofing, typically utilized on commercial flat roofs, to work well for a number of things.

For those applications requiring adhesion and/or sealing, cork tape works well too. It was once used commercially to seal the base of the glides for the sliding tops of Utility boxes. Don't know what they use now, but cork tape is also cheap and easy to work with. I know for a fact that it sticks, seals, and stays flexible for at least 50 years. I plan to use it between the frame for the scissor lift and the truck frame on my W200 project, which in other places are welded together.

[sweatybetty]

If you have gas spilling in the cab you have bigger problems