Rusty gas tank (inside tank rust)

What is the best way to clean the inside of this gas tank?

J C Whitney Lasalle Ill makes a kit that includes all chem to clean and seal the tank retails for about 35 dollars will require removal of the tank. I have used this kit 2 times one on Motorcycle tank and one on a (C) farmall. good luck.

(quoted from post at 19:08:07 05/03/09) What is the best way to clean the inside of this gas tank?

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muriatic acid, flush with water, pour in a couple gallons of E 85 to absorb any remaining moisture. I don't use sealer unless there is a leak.

If you just have some light rust in the very bottom and it is not causing problems with the fuel filter or sediment bowl, I would just leave it alone and keep water from getting in it in the future. If you are getting some rust and it is clogging the sediment bowl then put a handfull of 1/4 20 nuts in the tank and shake them around good to knock off the loose stuff and fish the nuts back out with a magnet. that will also grab up some of the loose stuff and it will come out with the nuts. Then rinse out several times till it is clean. I use a syphon hose with the tank tipped up so I can get the hose in the low end where the crud settles. One bad thing about using acids is it will take any of the old plating off the inside and then you HAVE to seal it with something or you really will have a problem. Some tanks were coated with Lead and some were coated with Zinc when new. Zinc is especially bad to get removed when cleaned with acid

Not sure if you ever get it all.

Last year on my 2606 with 18 gal tank still on the tractor. Poured 2 gals of muratic acid into the bottom. Let sit for a few hours full strength since that was where most of the rust was. Filled it up with water(just don't let the acid splash on you which is why the proper acid mixing method is to pour acid into water but I was usning a funnel anyway so no problem). Let it soak for a day. Muratic acid will flash rust very quickly. Used a garden hose to drain the tank over to a cedar tree I wanted to kill. Didn't kill it. Found some phosporic acid stuff at home depot. Put in a quart or whatever it was and rest water. Let sit another day. Sprayed it down with wd-40 water displacement to give it an oil coating. Problem is that there is a baffle just to the back edge of the filler hole. I couldn't get to that area nor could I spray wd-40 behind it.

Still getting a little rust this year. Under the tank I put a tee. Going straight down was a 4" piece of pipe for a drip leg to catch any rust. Out the side of the tee was a nipple going to ball valve and then on the sediment bulb (those sediment bulb valves don't always shut it off tight) I see a tiny bit of rust in the sediment bowl and once or twice, I've unscrewed the cap on the drip leg to clean out any rust.

I had put a couple wraps of window screen on the nipple (twisted a piece of wire to hold it) that screws into the tank to catch any rust and later removed it. I need to put one back in next time I have it apart. Some people put a piece of plastic/rubber hose on the nipple about an 1/2" to 1" long so it sticks up into the tank to keep the crud on the bottom of the tank from flowing in.

Just did a gas tank for the roto tiller this weekend. Mostly a varnish problem but some rust. Used Phosphoric acid (Behr concrete etcher 991-N in a grey jug, 45% acid solution, $20 for a gal at home cheapo)(Home cheapo had a gal of Klean-strip concrete etcher for $15 a gal but it has a 30 to 40% acid solution but probably the better buy). Glennster uses a 10 part water to 1 part phosphoric acid etcher to clean his rust off stuff. I probably mixed it at 5 to 1 for that little tank and left it for a day. Dumped it out and it left a little rust but most was gone from the bottom. Rinsed it out with water. Sprayed it down good with wd40 and swished it all over the sides and top of the tank. Didn't think about dropping something in to shake around to break up the rust.

Hi. Hang it firmly upside down, stick a high pressure water hose in the filler neck which is now at the bottom, and walk away. After about half hour turn off hose and allow to dry. Anything left in after that is unlikely to cause a problem.MTF