Hello.
Tried the search, but nothing came up.

I have the tank out (to install a sway bar), and like to use this "while your'e in there" moment to clean inside the tank as well.

The tank looks good on the outside.


All tips on cleaning the inside are welcome.

The most economical and environmentally friendly way is to go to Costco and buy 8 gallons of red wine vinegar. Plug all the tank outlets and pour the vinegar in the tank. Let it sit for a couple of days and turn the tank over so the vinegar can do its thing on the other half of the tank. After another couple of days drain out the vinegar and pour in a box or two of baking soda and then fill the tank with distilled water to neutralize the acid from the vinegar. After a few hours, drain it out ang blow compressed air or use a heat gun to blow out and dry the tank. When done, pour in a half quart of automatic trans fluid to coat the inside and prevent flash rust from forming. Move the tank around to coat all internal surfaces with the ATF, then drain it out and install on car. This worked great for me. It is amazing how it cleaned a gas tank I was going to throw away because I thought it was a goner. Learned about this on the Samba.com website. Seems that motorcycle guys do this a lot too in order to remove rust from old motorcycle gas tanks. If you look on YouTube there are a few videos of it being done on motorcycle gas tanks.

If you have extreme rust issue you can do it via electrolysis. The difference here is you ground the tank, and suspend the positive lead.

If your not going to fire it up for a bit, keep it out and run ATF in it every now and again spin it and keep the rust down to none.

Also do not forget to check the screen in the tank. Tangerine sells them if you need a new one.

I agree. I did this on my two motorcycle tanks and do it all the time with rusty hardware. Our local grocery store sells gallons of apple cider vinegar for $2.50 so its pretty economical for me.

Vinegar works very well. The ATF rinse is new to me and sounds like a
great idea.
I heard of using muriatic acid which is not only dangerous but difficult to handle
and dispose of. Don't do it.

I tried the acid thing. Gotta wear gloves, eye protection, ect. Mix with baking soda to neutralize. But Rory is right, it's dangerous and vinegar does the same thing, just a bit slower.
One of the reasons I like using vinegar is I can do this stuff in my garage and if I spill, I don't even bother to wipe it up. If my dog licks it, no problem. No complaints from my wife about the smell - she says it reminds her of boardwalk fries.

If a couple days isn't enough, just pour the vinegar back in and wait a couple more days.

I used that magic rust remover chemical that some use - spacing on the name. Filled up the tank and rolled it over periodically in the front yard in the hot sun to speed the reaction.

Then I put the tank on a rotisserie (literally) and filled it with a few big nuts and bolts and pieces of chain and a bit of WD40. Drove that with a garage sale rotisserie motor for bar B Qs and let her rip for a day or so. Sounded like an advancing armor brigade only louder. Polished nicely.

Sort of my average way of doing things. Have done this with two 914 tanks and the TR6. So far so good.

Here is the TR tank in motion.

Click to view attachment

This was the first one and used a slightly different drive mechanism.

Interesting tank rotisserie, been thinking about building one for a while, I have two tanks that need to be cleaned before they go in.

For the vinegar methods: Does the gas-gauge need to come out?

I would because it gives you the opportunity to install a new rubber seal.

I cleaned mine out it out through electrolysis, based on a couple of threads on how to do it.

Fill up your tank with water, add in about 1 cup of washing soda.

Take a battery charger, ground to the tank & insert some rebar in the filler hole (insulated from tank) and attach your hot lead to it. I did this on a 10 amp charge and it took me several days until it was all cleaned out.

I got the caswell 2 part epoxy tank seal kit.

You can also call a radiator repair shop and see what they charge to clean it out.

Here's the how to thread
http://www.914world.com/bbs2/index.php?sho...l=washing++soda

Yep, Arm & Hammer washing soda and a battery charger. Worked awesome.

Not baking soda.

Works great
Click to view attachment
Click to view attachment

Has anyone used the fuel tank coating products after cleaning the tank? Products like Red-Kote or POR-15 Tank Sealer?

What was the rust hunk before you started cooking?

After the final rinse leave it out in the sun for an afternoon. You being in Texas I imagine it will get plenty dry.

Theres no reason to if you keep fresh gas in the car.

I haven’t cause I have seen various polymers separate from steel in the presence of solvents like gasoline. If that happens, the carbs and or injectors lie downstream. But I shine a flashlight into each tank at least once per year.

There was a thread on Red Kote not long ago. No experience with it myself, but interesting reading: http://www.914world.com/bbs2/index.php?showtopic=324029

I've used those and Kreem and never been happy.

You really want to go with the Caswell Platings kit or nothing. It's the only 2-part epoxy kit out there and it works great!