Muriatic Acid

[JStinson]

Alright folks, the fight is back on to restore the M38A1 gas tank for my dad. He bought a new one, but it is made in the Philippines and out of spec. I guess you could call it a "will fit" unit.

Either way, I want to fix the old tank. Though it's not my truck, the tank issues are driving me nuts.

http://www.ratwell.com/technical/Fue...storation.html

Here's a link to a great set of instructions on restoring a tank using muriatic acid and the POR-15 restoration kit.

My question is this: this particular tank has an outside coating on it. It's a coat of sealer, presumably plugging up some holes in the tank. I want to strip this coating off and use the POR-15 restoration kit to reline the inside. Is this necessary? Would cleaning the inside be sufficient? How would the muriatic acid affect the outside coating (because it will inevitably touch it in at least the spots where the coating is sealing up the holes).

Thoughts?

[Ron in Indiana]

Not knowing what the coating is you may be opening a can of worms. My advice to save a lot of trouble would be to have it done at Gas Tank Renu dealer. We've had several tanks done and we are very satisfied. We lost our local dealer so the last tank was shipped to a Detroit dealer , treated and returned. It's not a cheap process but carries a lifetime warranty. I don't trust the liner in a bottle fix. I relate it to Fix A Flat, it'll get you by but sooner or later it has to be repaired correctly. They will coat inside and out for a worry free tank. Is it worth the hassle dealing with acid and disposing of the leftovers? Gas Tank Renu and be through.

[Matt Wilson]

I second what Ron says. I'm not saying that a DIY coating could never work, but my experience was not positive. I used the Bill Hirsch coating - supposed to be FAA approved for use in aircraft - and I believe I followed the instructions to the "T" the whole way through. The coating adhered to the inside of the tank for several years, but eventually it let loose. Fortunately it didn't cause me any problems, and I found it by chance when I had the tank out for other reasons, so I pressure washed the rest of it out. Turns out I probably didn't really need to line the gas tank with anything. I had thought it was rusted when I first got the truck, and I thought the rust particles were clogging the carburetor, but I believe my problem was actually vapor lock. So I installed an electric fuel pump and have never had a problem since.

Other people have claimed very good results from the Gas Tank Renu services. One day, I will try them if my tank causes me problems.

[W_A_Watson_II]

I used the POR-15 kit on my M's fuel tank, and so for (knock on wood) it's been great, even after 6.5 years. Now to hope it stays that way after mentioning it here.

[JStinson]

The biggest question that I have is this: Should the old external coating be removed or can it be kept?

[Matthew Ziegler]

por

I used the por kit about five years ago an my m37, had the tank boiled out by a radiator shop, then followed the instructions, It lasted about 3 years, I blame ethanol, my fuel filter was full of what appeared to be silver paint. I found a company called caswell, they make a 2 component sealer which is supposedly indestructable. just my two cents

[DrPepper]

silly question...

If the tank is solid and isn't rusted bad, inside surface rust only. Can't you clean it up and get the gunk out, make sure it has a good filter (or 2) and leave it alone?
DrPepper

[JStinson]

If the tank is solid and isn't rusted bad, inside surface rust only. Can't you clean it up and get the gunk out, make sure it has a good filter (or 2) and leave it alone?
DrPepper

That's exactly what I did.

Before:



After:


There are still some stains on the top of the tank, but it really is about a zillion times better.

[JStinson]

Pictures

Before



After