Cleaning a Gas Tank

29Cabriolet

29Cabriolet

Senior Member
Hi:
Looking for some advice on how to effectively clean a gas tank. This tank is from a '29 which has the steering column support bracket riveted to the bottom wall of the tank. As with many, stress at this point has caused the area to weaken and develop a leak. The tank had already been repaired many years back what looks like a braze or solder job. Apparently that was inadequate because later, epoxy and other sealers were applied over that.

I've removed all the epoxy and am down to bare metal in that area. To redo the repair, I am considering brazing or soldering again (by someone more qualified for the task than me) but of course I want to be sure that the tank has expelled all gas fumes and won't explode! At the same time this is a good opportunity to clean out the inside of any rust or residue that may exist. Prior to removal the car had been driven all last season. I began this project in January, the first step of course was to drain the tank. So it has been empty, open and uncapped since then. What is the best way to do this?
Thanks!
 
Just came in from the super market-have been looking for reasonably priced vinegar
and is going for close to 4.00 a gallon.
just bought 6 gallons today at 1.88 a gal
pouring a couple into my Maxwell tank-let it sit for 30 days, then do each side and finally spin it upside down-will be nice and clean in about 3 months time.
Yes it is out of the car and much easier to work with.
Another good option is to go to a rad shop and have it boiled out...........
 
ronn said:
Just came in from the super market-have been looking for reasonably priced vinegar
and is going for close to 4.00 a gallon.
just bought 6 gallons today at 1.88 a gal
pouring a couple into my Maxwell tank-let it sit for 30 days, then do each side and finally spin it upside down-will be nice and clean in about 3 months time.
Yes it is out of the car and much easier to work with.
Another good option is to go to a rad shop and have it boiled out...........
Click to expand...
Thanks for the reply. But Yikes! 3 months? My goal for this project is to get the car back on the road before the season ends. I've read a few articles about vinegar doing the trick but those were focused on rust and debris rather than gas fumes. Need to be sure there are none before hitting it with a torch!
 
If youre just worried about fumes-either run water through it and then dry it out with a shop vac or just use the shop vac to blow it out with air.
You might be surprised at what's in your tank...............
at the very least, shine a light around the inner base to see what you are working with.
 
Flushing it out with water and then a few rinses with a strong mixture of some good old simple green will probably do the trick. I would shy away from using a shop vac on any gas tank unless it has not had gas in it for MANY years. Pulling gas fumes through an electric motor has bad written all over it.
 
When the tank is empty just stick an air hose in it and purge it for 30 or more mins. That should clean out the fumes. Thats the way we did fuel cell repair on airplanes when I was in the AF, except we use a blower with lots of volume but the tanks were a lot bigger.
 
I cleaned out a 29 tank with a pressure washer, water and detergent and let it dry for a few days. Remove the dash gas gauge so you can direct the spray around. I would bring it to a radiator shop and coat the cracked area with solder using a large solder iron. No danger with fumes with a large iron. Don't use that lower bracket to hold the steering column.
 
The leak is not always under the soldered bracket. I have seen cracks 3/4 to an inch below the bracket.

Radiator shop drilled a small hole at each end of crack to stop it from going further and soldered a brass patch over it. Then you can install the improved 30-31 steering column bracket to prevent further damage.

This area can not seen unless you look under the tank.
 
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Watched my dad weld many gas tanks back in the day. He aways remove, drain then flush the tanks with exhaust gases from a running motor with a hose or pipe for one hour. Warm exhaust gases evaporated and evacuated left over fuel and gas in the tanks.

Mark
 
ronn said:
If youre just worried about fumes-either run water through it and then dry it out with a shop vac or just use the shop vac to blow it out with air.
You might be surprised at what's in your tank...............
at the very least, shine a light around the inner base to see what you are working with.
Click to expand...
The voice of experience and seven stitches in my left eyebrow and much water under the bridge says that just running water through your tank won't help. Also using a vacuum cleaner with electric motor is likely to cause things to get very exciting, not a good idea with fumes in the tank.
The OXYGEN MUST be removed from the tank. I removed my tank and took it to the radiator shop to be boiled out.
Use caution as a gas tank is a BOMB if not handled properly. Good Luck on your repair. Some times on these repairs the hard way is the easy way.

Chet
 
Marklambert61 said:
Watched my dad weld many gas tanks back in the day. He aways remove, drain then flush the tanks with exhaust gases from a running motor with a hose or pipe for one hour. Warm exhaust gases evaporated and evacuated left over fuel and gas in the tanks.

Mark
Click to expand...

Don't forget that the exhaust displaced the O2. You can't have combustion without oxygen.

Chet
 
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