Just bought a 1952 Pontiac. Still have the straight 8 in it. I pulled the gas tank. Been sitting last 10 years. I have never seen such a mess. Inside the tank was a 1/4" thick varnish/old sealer jelly like substance. I was able to tear off a few sheets of it and look at it in the light. Hard to tear apart, mean looking crud. Lacquer thinner, gasoline barely touched it. I went to the hardware store and found a sulfuric acid based drain cleaner. Says " Danger for professional use only" and inside a quart jug and a plastic bag. Common stuff. Came back and dumped it in. Started a reaction right away. Making a rotten egg fog that seeped from the tank. I could feel the heat as it chemically reacted with the tough jelly on bottom of the tank. Let it sit overnight and before work, with eye protection, dumped in a quart of acetone. It was still hot. Came home from work, and it had worked. Totally dissolved the jelly and I poured out a black substance like melted tar. Pressure washed tank, and presto, 99% clean to the shiny metal floor of the tank. Now I can deal with the last bit. Just thought I'd share. Man that stuff worked great. Now I just have to find out where #1 tdc is on these straight 8s so I can time it. Blasted around the yard pretty good right now with a temporary tank in place. Need to free up the valve body on the '52 hydro.
Sounds like a good method! Any before and after pics? Thanks for sharing! Regards, Randy Sent from my iPhone using H.A.M.B.
Just please make adequate use of protective gear for hands, eyes and especially inhalation when doing this stuff. That mix of drain cleaner and acetone sounds like an effective but very dangerous witch's brew.
I used a product called muratic acid,it worked great even took the rust of inside my tank,the bad thing was i didnt treat it right after and my tank started to rust on the inside,got so bad that the filter was plugging up all the time,it was a real mess,make sure you use a sealer of some sort,I had to cut my tank open and sandblast it and used a epoxy coating to seal it up,all is fine now. Harvey
Or buy a new one from Tanks. http://www.tanksinc.com/index.cfm/page/ptype=results/category_id=133/mode=cat/cat133.htm
If you can find one that is a close fit, yes. I don't like to piss around with old gas tanks and prefer to replace them rather than monkey around with one. Exact-fit for an old Poncho, good luck.
I found a couple pounds of large blue stone into the tank with Dollar Store " Awesome" cleaner .....I jack up the rear of our kubota tractor and strap the sealed gas tank to the rear tire.....put it in first gear and let the tire rotate at idle speed for 3 or 4 hrs and Presto and spotless clean tank.....done with many..
I have a friend that owns a lawn mower business. He swears by cheap Dollar General brand toilet bowl cleaner to clean old gas tanks. I have had friend try it and they said it worked great.
I just was checking the Ace hardware site, and I believe it is Rooto Professional Drain Cleaner. Quart bottle enclosed in a plastic bag and says "for professional use only". Described as Pure, strong sulfuric acid. It did smell rotten egg like, and created heat as it worked. After I finished the cleanout and washed it, I used a product I get at the auto body supply. It is called "Rust-Mort". This is phosphoric acid. You can't buy this strength at home depot. It turns any flash rust black within a couple minutes. I rinsed it with gas afterwards. I drive the car a couple times a week, and have changed out the inline filter once. Worked great.