Cleaning a Gas Tank
 

I am trying to finish a late 31 Coupe project that I started about 12 years ago and did a few things over the years like accumulating interior, changing the Rumble Seat to a trunk, getting a leather seat done, etc. I needed to get it running so I could move it to the work area. It runs OK with a 1 gal gas can on the radiator rails. I drained the gas tank and not much came out until I put some air into the external drain. I put it outside and put 10 gallons of water into the tank and it mostly came out without much trouble. The last liquid residue in the tank is very red and smells terrible. There did not appear to be much rust in the water drained from the tank as I was planning to follow some advice here and use Rust 911 as the last step. I have a gallon of 5% vinegar to use as the first step to clean up the unknown red residue.


I am looking for advice or warnings before I put gasoline into the tank after all the cleaning steps are completed. I am concerned about the acid in vinegar. Your thoughts please.


Vic

Re: Cleaning a Gas Tank
 

There was a great video on youtube at one point that showed how to clean it out fairly well. IIRC it involved like a gallon of acetone to dissolve all the varnish from the old gas. Rock it then drain through a painter's filter. Run a few gallons of gas through it, rocking it a bunch and then through more filters. Repeat until its fairly clean with no more residue or particles. then throw a pencil filter on the shutoff and run with it.

I did that with great results.

Re: Cleaning a Gas Tank
 

I also placed a strong magnet under my tank in a hidden place to collect any small particles of rust or powdered oxide.
Ed

Re: Cleaning a Gas Tank
 

Yes, after thorough cleaning, put a strong magnet on the bottom of the tank.

Re: Cleaning a Gas Tank
 

Get all the water out, alcohol mixes with water and should evaporate faster. A great magnet can be taken out of any old microwave oven. Should find one on trash day. The magnet is very strong! round, 2"diameter, 3/8ths thick with a hole in middle. Like said above, a pencil filter in outlet is good to have.

Re: Cleaning a Gas Tank
 

I like the idea of a gallon of acetone to clean out the red varnish. Why is the varnish red? With the late 31 tank there is no place for a pencil filter in the outlet of the tank that I can see. The outlet is horizontal. I have a few small and powerful magnets.


Vic

Re: Cleaning a Gas Tank
 

Paul Shinn did a video on this. Make sure you invert the tank as lot of rust collects on the top of the tank,

https://www.bing.com/videos/rivervie...8C18&FORM=VIRE

Re: Cleaning a Gas Tank
 

The pencil filter fits into the gas valve "before" you put the valve into the tank. It stands upright in the tank.

Re: Cleaning a Gas Tank
 

The pencil filter only works on cars before they had indented firewalls.

Re: Cleaning a Gas Tank
 

But then how do you get it out of the tank? The rust particles will build up in that spot but somehow need to be removed. Personally, I place a round rare earth magnet in the float bowl. This sees all the gasoline, not just that that happens near the spot, can be easily monitored, and then can be cleaned and removed.

Re: Cleaning a Gas Tank
 

Do not put it in the tank. Attach it to the bottom of the tank. Remove it occasionally and use a magnet on a stem inside the tank to collect the area where the magnet was located.
Ed

Re: Cleaning a Gas Tank
 

One of the common sealers is a red color so I would want to look in there to see if there has ever been any sealer put in there other than the factory coating. I use a bore scope to look inside. I can see top and bottom surfaces and it's long enough to peer over the edge of the baffles to see how the outsides look. A person can carefully scrape a little bit off the bottom to see if there is rust in there. If it's rusty then it has to all be removed to reseal.

I used to use Drano crystals when there were thick varnish deposits in a tank. The original Drano is no longer available so now I use Black Swan crystals. Caustic soda will remove about anything and it only takes a day or so. The caveat of using it depends on the condition of the original tank lining. Model A tanks were internally coated at the factory with tern plating. Caustic soda will remove everything in there but the steel and the corrosion. The baffles make the corrosion removal a very difficult thing unless the tank is cut open. This is a very time consuming task so unless a person is equipped to do it themselves then it will be expensive. If corrosion is light then it can be chemically removed but if it's heavy and repairs are needed then that won't work.