Fuel Tank cleaning Options

[worn]

I like the evapo rust. But it works better warm and it doesn’t last forever. Hard to know when it is no longer active.

[Highland]

Thanks for the advice, Rob.

Chemical burns? Yikes. What would you have chosen instead of duct tape?

Long time ago, I remember someone recommending taking a tank to a radiator shop for boiling. I wonder if that would strip the paint off the exterior? I'd rather not have to paint the outside.

I had my tank commercially "boiled out" without realizing that process would also remove the external mounts for the vapor tank and charcoal canister. I later discovered I could have bought a replacement tank for less that the boiling cost. (IMG:style_emoticons/default/confused24.gif)

The external mounts are not welded? Can they removed and mounted on a new reproduction Dansk tank?

[Jamie]

Thanks for the advice, Rob.

Chemical burns? Yikes. What would you have chosen instead of duct tape?

Long time ago, I remember someone recommending taking a tank to a radiator shop for boiling. I wonder if that would strip the paint off the exterior? I'd rather not have to paint the outside.

I had my tank commercially "boiled out" without realizing that process would also remove the external mounts for the vapor tank and charcoal canister. I later discovered I could have bought a replacement tank for less that the boiling cost. (IMG:style_emoticons/default/confused24.gif)

The external mounts are not welded? Can they removed and mounted on a new reproduction Dansk tank?

Apparently they are soldered in place rather than welded.

[914sgofast2]

Rusty:
The best and most economical way is to go to your local grocery store or Costco and buy 6 gallons of white distilled vinegar. Then go to your Home Depot, Lowe's, or ACE Hardware and buy two plumber's test expanding rubber tipped plugs: one for the big hole for the gas tank filler neck and a smaller one for the gas tank sending unit hole. Alternatively, you can leave the sending unit in the tank with no ill effects. Leave/put back all the small threaded bolts that hold down the filler pipe and the gauge sending unit screwed into the tank to seal up the small mounting holes.

Next just put a length of fuel line hose to connect the two bottom tank outlets; or, as I did, remove both of the the outlet pipes and connect a piece of old heater hose (either 5/8" or 3/4" inside diameter - I can't remember) from one threaded outlet to the other on the bottom of the tank.

Pour all the distilled vinegar into the tank and replace the plumber's test plug. Let the tank sit on its side for a day. Next day turn the tank over so the vinegar can cover the other inside half of the tank.

On the third day, drain out the vinegar and refill the tank with a combination of water and a box or two of Arm and Hammer Baking Soda to neutralize the acid. Let the baking soda and water sit in the tank for a couple of hours, then drain it out and flush the tank with water to rinse it all out.

Then dry out the inside of the tank using a hair dryer pointed into one or both of the big holes.

Once the inside of the tank is dry, pour a quart of Automatic Transmission Fluid into the tank and slosh it all around to prevent "flash rusting". When you are ready to put the tank back into the car, turn the tank upright and drain out the ATF and put the tank back into car and fill it with gas.

You will be amazed at how this cleans out all the rust. I learned this from watching YouTube videos on how to clean motorcycle gas tanks and used it on my 914's tank a year ago. It worked perfectly. No need to worry about disposing of hazardous chemicals or breathing dangerous vapors from the various snake oil products sold by Eastwood, Por15 or others looking to empty your wallet. No need to use expensive gas tank coatings of dubious effectiveness on the inside of the tank.
Mike D.

[IronHillRestorations]

I used to have a small coffee can with KEPS nuts, chain, fence staples, bolts and sheet rock screws that I used to clean a tank. I don't mind cleaning the tank so much, but the old bad gas; now that's nasty