rehabing an old gas tank

Syphon out all the old gas you can and put a gallon of solvent in and drive it around for a week to losen up stuff.

there is stuff called "sloshing compound" used on aircraft gas tanks, also sold to the antique car hobby (where this is common - my 36 cad had a hole in the gas tank you could put a gerbil through). clean the tank, if you suspect the metal, you can use the sloshing compound.

I have heard that a phosphoric acid solution will clean gas tanks out very well, not sure of the concentration needed, but probably low, follow with boiling water & baking soda rinse to neutralize, blow out with compressed air, and then acetone or alcohol rinse to displace any moisture left by the water/soda rinse.

Do a little "google" research.

-Tom

Acetone will dissolve that varnish. It will take a bit of agitation, though. I'd drain the tank, get a long inspection mirror, and look around in the tank to see where the level of the varnish is. Good luck with doing it with the tanks mounted on the truck. Perhaps a drive over a bumpy road?

Gary

Eastwood sells a kit for this purpose:

-Ron

You might also drop in a handfull of big lead shot to agitate and burnish. Won't hurt to leave it in there after they are put in service.

Eastwood is an auto restoration supply house. Great catalog, prices are a bit steep, but lots of unique things you can't get elsewhere. They have a line of products for gas tank repair and reconditioning. If you can't google 'em up, I'll check for an address for you. Great customer service.

It goes without saying, I hope, that you should never approach a gas tank with any sort of flame or cutting tool. I went to a call

Dave Hinz

Take them to a radiator shop and have them hot tanked. Oh,....let them keep the varnish.

Best advice so far. It's not that hard to drop the tanks. You will also have to inspect the level sending units. "Hot tanking" is what the professionals do for a good reason.