Rusty fuel tank.

[Aok]

Originally Posted by Brentwood Bob

The attempts to clean the tank in vivo will be a good first project.
Look up dirty leg and install one.
Until you remove and have the tank boiled out you will need the dirty leg.
Bob

My tank was not real rusty but enough flakes to to slow up gas flow.
I stalled the "dirty leg", basically a drip leg coming off the bottom of the tank. It it works well for me no more fuel problems.

[jdp8402]

I've always been told the key to not getting rust or moisture in a tank is to keep it full. Especially if it's going to sit a long time.

[Mitch//pa]

adding MMO to the fuel wil help coat the tank

[Greg Jones]

With today's ethanol contaminated gas I would completely empty the fuel tank for a car going into long term storage. Ethanol attracts water big time.

[Nathan_1929]

Originally Posted by jdp8402

Does vinegar dissolve the rust or just break it loose from the metal?

Seems to do both.

Originally Posted by jdp8402

Have you used evaporust? If so how were the results?

Forgot about that one. I've used Evaporust and it's quite handy. I'm cheap so I drain it, strain it, and re-use it. Still works.

[jimcarl]

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First, thanks to all for everything I've learned from this forum. It's an invaluable resource! Next, my question is: if I use evaporust to de-rust my gas tank, how much effort does it take to thoroughly rinse the tank after treatment if the tank is still on the car? Thanks!

[DJ S]

I can't imagine overly difficult if you have a dogleg installed. Just run a gallon of gas into the tank and shake the car around then drain. Do this few times, then fill the tank to the top with gas and with some MMO added to it to help prevent reoccuring rust.

[jdp8402]

Originally Posted by DJ S

I can't imagine overly difficult if you have a dogleg installed. Just run a gallon of gas into the tank and shake the car around then drain. Do this few times, then fill the tank to the top with gas and with some MMO added to it to help prevent reoccuring rust.

When you say "MMO", are you talking about Marvel Mystery Oil?

[Mitch//pa]

Yes

[jimcarl]

I'm not as concerned about the large chunks as I am about the residue left by evaporust. Since the baffles prevent rinsing the surfaces directly, does rocking the car with water in the tank do a good enough job of cleaning off the residue? I can't imagine any residue mixed with gas would be a good thing!

[mrtexas]

The residue is easily washed away. I'm not sure but I think the residue is the carbon from the rusted steel.

[mrtexas]

Originally Posted by jdp8402

I think I'll give the evaporust a try. What all has to come apart to pull the gas tank off?

At $25 a gallon and you are going to need 5+ gallons you are much better off buying the generic.

[jdp8402]

Originally Posted by DJ S

I can't imagine overly difficult if you have a dogleg installed. Just run a gallon of gas into the tank and shake the car around then drain. Do this few times, then fill the tank to the top with gas and with some MMO added to it to help prevent reoccuring rust.

I've been doing that whenever I can find time for the past three days. I'm worried about all of the rust that is stuck to the tank yet. I know it will come loose eventually so I want to try to take care of it now. My tank is pretty bad. I've purchased some evaporust from amazon. They were the cheapest I could find but it's still going to be a costly experiment. I'll try to take some before and after pictures.

[jdp8402]

Originally Posted by mrtexas

At $25 a gallon and you are going to need 5+ gallons you are much better off buying the generic.

I found it on amazon for $84.50 + free shipping for a five gallon bucket. I bought two of them because on the directions it says to completely fill the tank. The reason I decided to try it is because it's reusable. I can find all kinds of rusty things to soak. It would probably be better and cheaper to take the tank off and have it boiled out but I don't want to have to paint the tank yet.

[Tom Wesenberg]

Also you need to be careful about having the tank chemically cleaned by some shops. A guy in our club had his 29 tank dipped and it came out of the solution without the threaded fill neck. He sold it to a hot rodder and had to buy another tank.

[Mitch//pa]

Originally Posted by jdp8402

I found it on amazon for $84.50 + free shipping for a five gallon bucket. I bought two of them because on the directions it says to completely fill the tank. The reason I decided to try it is because it's reusable. I can find all kinds of rusty things to soak. It would probably be better and cheaper to take the tank off and have it boiled out but I don't want to have to paint the tank yet.

thats a good price and the right move to fill the tank all the way to the top. sometimes generic medicines are not as good as the real stuff.. being frugal or going half way can give mixed results..

[BRENT in 10-uh-C]

Originally Posted by jdp8402

I found it on amazon for $84.50 + free shipping for a five gallon bucket. I bought two of them because on the directions it says to completely fill the tank. The reason I decided to try it is because it's reusable. I can find all kinds of rusty things to soak. It would probably be better and cheaper to take the tank off and have it boiled out but I don't want to have to paint the tank yet.

Again, as I asked above.... When the Evaporust has removed the rust from the walls/baffles of the tank, then what? How are you going to stop the bare metal from re-rusting again?


Also, another point that should be made. "Boiling out" a tank at the radiator shop is a comment that is often used, ....and I feel often misunderstood. While these days it is rare to still find a radiator shop that still uses a caustic tank, it is possible. Now here is where all of this is wrong.

First off, Sodium Hydroxide in their tank will generally be in a 10-15% solution. Sodium Hydroxide is great at removing anything that is organic ( i.e.: old gas, varnish, paint, old tank sealers, rubber, wood, leaves, etc. ) however it does nothing to steel. This is why you see it contained in a metal vat. If it truly dissolved rust, given some time (a few months) it would eat a hole thru the side of the vat too. As Tom mentioned above, it does however disolve soft metals given time. I have put engine blocks into my hot caustic tank without removing the rear seal and it would be partially dissolved when removed from the tank.

With that said about the soft metals, the tanks originally were a Terne-coated metal before they were stamped. This Terne coating was the rust preventer inside the tank. Hot caustic does dissolve the Terne coating. So when a tank comes back from a radiator shop after being hot tanked, folks look inside the tank and see shiny bare metal at the bottom of the tank and tell the rad. shop owner "Good job!". The issue is that most of the rust we find on tanks is on the top of the tank. This is an area you cannot see, and the hot caustic bath did nothing for that. If the rad. shop owner used a steam cleaner to flush the tank with, the pressure knocked off the loose particles & sediment however the metal is still bare inside. Guess what bare metal is going to do now?? So this brings me back to my question above, - How are you going to stop the bare metal from re-rusting again?

.

[jdp8402]

Not sure I guess. What can I do without removing the tank?

[BRENT in 10-uh-C]

Originally Posted by jdp8402

Not sure I guess. What can I do without removing the tank?

I think good advice has been given regarding the stand-pipe, -and my only other suggestion would be to salvage several strong magnets out of some junk audio speakers. Place these magnets on the backside and underside of the fuel tank to attract & collect floating rust and sediment. Then periodically, drain the fuel from the tank, remove the magnets and pressure wash the inside of the tank the best you can to flush out the rust. Then reinstall the stand-pipe and magnets, ...and go again until you can properly restore the tank.

[Rowdy]

I have just began to repair a tank using Brents method. While it is not the best tank I have it is the only one with the correct firewall date that closely matches my engine/frame numbers. I gave up finding a nice tank with the right date range and swapping firewall sections on a better tank is almost as much work. Will post results some time this winter as I likely wont get back to it until after the ground is covered with snow. Rod