How to pop a dent out of a gas tank?

Zachary Hoyt · Jan 11, 2013

I would like to use this tank on the C I am putting together since the other tank I have is dented much worse. I am wondering if I can stick a bent rod in through the fill hole and hit it with a hammer or if there is a better way. I know glennster mentioned using a stud welder to fix a squashed tank, but I am in a little bit more primitive situation than that. I know how to straighten the hood with some wood blocks and a big rubber mallet, but the tank is confusing me a bit. Any advice will be much appreciated.
Zach

DownSouth · Jan 11, 2013

A bit of gas and a match?
Seriously, I would be concerned about the seam after getting it straightened out no matter how you did it.
How about doing it the Redneck way? Beat in the other side to match, paint it and go!

old · Jan 11, 2013

That be a tank off an Allis C?? If so make sure you can remove the sediment bowl assembly before you go into it more. Many of those old tanks rusted out at the bottom and when you try to remove the sediment bowl assembly the bottom of the tank will twist out so you have a tank that is not good for any thing. I have 2 very good looking tanks with not dents but the bottom twisted out when I tried to remove the sediment bowl assemblies

jon f mn · Jan 11, 2013

I doubt you will be successful, but you could try air pressure. Close the exit hole, plug the fill with a shop wrag and use your blow gun to presure it. Then hit it at the crease with you "big rubber hammer". If you look at your picture you should tap it right at the top of the crease at the end of the light reflection on the top corner of the tank, and also the same spot on the bottom of the tank. By tapping there with your rubber hammer with air pressure inside it may pop out. It won't fix the crease, but the main dent may pop out.

JD Seller · Jan 11, 2013

For the time and effort involved I would just find another "Good" used tank. The AC parts are not hard to find and usually are not high priced.

Call this fellow. He is very reasonable on AC parts:

AC Tractor Salvage

Specializing in Allis Chalmers tractors only with aproximately 300 units in the yard. From the model 7000 and older with most models available. We try to maintain reconditioned parts and after market parts from various sources. We also rebuild good useable tractors and do some restoration and custom

8480 225th Ave
Maquoketa, Iowa 52060
USA

ph: 563-652-2949

gab · Jan 11, 2013

You got a slide hammer? Weld a nut that will screw on to the slide hammer to the bolt on a vise grip and try massaging the seem out.

Ray · Jan 11, 2013

Buy another tank,C parts are cheap.You can buy a whole tractor for a few hundred bucks.

rankrank1 · Jan 11, 2013

A few options:

a) Well, I have heard of filling motorcycle tanks with water and then placing in freezer. Take a big freezer for that tank though and sometimes the water expands where you do not want it to.

b) After a tank is properly purge of gas vapors, fumes and all possible residue (not easy but it is possible but takes great care and caution), I have also heard of sealing the tank openings securely such that 6-8 PSI (or maybe 10-12 PSI) of air pressure can be pumped into the tank (install tire valve in one of the sealing plugs). Heat the damaged area with a torch and let air pressure push it back out. Not too cherry red though or air pops a hole.

c) Stud gun as already mentioned (tank still needs purged of all vapors first).

d) Drill holes use traditional dent puller then reweld holes (tank still needs purged of all vapors first).

e) Weld crude patch over caved in to somewhat fill void partially and then bondo rest of way (tank still needs purged first).

f) Cut repair section out of other damaged tank that you have and then tig weld repair section into this tank (requires purging of both tanks and likely a smidge of bondo).

g) Fill current void with huge mass of Bondo (no purging required).

h) Leave it as it is.

I) Find another tank (easiest and best option)

GeneMO · Jan 11, 2013

with the dent in that seam, forget it.

Only way is with an auto body, spot weld type of stud puller. And that makes a spot weld so gas vapors are an issue.

Buy a good used on.

Gene

WAYNE-N-TX · Jan 11, 2013

Don't waste your time freezing water to make it straight, for sure it will not work. Go ahead and get another.

rankrank1 · Jan 11, 2013

(quoted from post at 04:13:01 01/12/13) You got a slide hammer? Weld a nut that will screw on to the slide hammer to the bolt on a vise grip and try massaging the seem out.

Zach - gab's just might be the winner. Forget my long list of options that I posted earlier. I would try this one as I like it. If it did not work out then not really out anything other than time. You can always find another tank if it does not work.

John B. · Jan 11, 2013

I would not use air pressure to push out the dent. You can't control the expansion of a vapor. I would use a port-a-power and fill the tank with a cheap grade of oil then heat the dented area. When under slight pressure and it's heated the dent will push out slighty and pressure will be gone and you'll have to pump it up again. When using a liquid it is controllable since it can't be compressed, it can only pressurized and any little movement in the vessel will relieve that pressure in an instant. So you can push the dent out slowly. Compressed air will keep pushing until the pressure is gone or the air has completely expanded. We use to push dents out of hydraulic cylinders on fork lifts all the time this way. We heated up the dented area and used the vehicle's hydraulic system to push the dent out. We were taught never to use compressed air, even 6-8 lbs can cause injury or death. It looks like you have a dent 8" x 10" so this is 80 square inches and at 6 lbs of air pressure you have 480 lbs pushing on that area. It never quits pushing until all the air pressure or air has expanded. Not a good idea to use compressed air. Any gasoline fumes that may be in there and put under any pressure are highly explosive.

Janicholson · Jan 11, 2013

Clean and rinse the tank. Drill a 1.5 inch hole opposite the dent. Use rounded end steel rods, and hard wood sticks to pound out the dent through the hole. Pound into sand bags or soft earth and it will be easier to control the result. You can also put flat metal into the tank to push on with the previously mentioned rods. Once the dents are taken to your satisfaction, have a disk of metal welded back in the hole.
Remember a used good tank is probably a reasonable alternative. If it were one of three tractors with that tank, investing time is a rewarding experience. Otherwise not. Jim

Goose · Jan 11, 2013

Stand about a hundred yards away with your fingers in your ears while someone else welds the patch on the tank.

I blew one up once, after I thought I had it washed out sufficiently. It was not an experience I'd like to repeat.

320B · Jan 12, 2013

If you do decide to weld on it or heat it up run a pipe off the exhaust of a running vehicle into the fill hole of the tank. No air no boom, just make sure someone is making sure the pipes don't fall off while your working on it.

Mike (WA) · Jan 12, 2013

The metal is stretched at both ends of the dent, especially at the bottom. If it was a fender, where you can get to both sides, you could repair it with heat and then quench to shrink it, and some hammer and dolly work. But since you can't get to the inside to work the metal, it would be pretty much impossible to repair. Time for a different tank.

gene bender · Jan 12, 2013

You better sand blast it and your friend would be Bondo. The seam is where the top and bottom were welded together and you try and bend in that area the seam will bust as that rib gives it strenght. Then you will have a good leak. I used Muratic acid on one trying to get the dried gas residue out and turning it over to move the acid around i noticed a small leak coming from that area. Thats why i wouldnt mess with it because of the weld.

IaGary · Jan 12, 2013

Knowing where that tank is located, how would a dent like that happen?

Straight side force where there is a wheel in the way to get to the tank.

Tree would be down force as would anything else falling on it.

Almost had to be run into on the side from a loader or something in the air.

Tractor had to be still with something running into it up high.

Gary

plow hand · Jan 12, 2013

buy a good used tank..good luck!

Zachary Hoyt · Jan 12, 2013

The allis C wheels are small enough (24")that it would be easy for anything approaching from the side of the tractor to hit the tank. The fellow I bought it from has a skid steer with forks that he uses to move things around so it probably was the cause of the dent, I am guessing.
Zach

DoubleR · Jan 12, 2013

One way a dent like that could happen is someone like my daughter backing a loader tractor out of its tight parking spot in the barn with the bucket about half way up. Then hitting the piece of equipment parked beside it with the bucket. Looking back wards and cutting the wheel hard one way. The same way I got a panel in a garage door toward the top taken out. My son plowing snow and watching the rear blade and not the bucket on the front of the tractor. They were both adults when this happened. I guess I just didn't raise them right.
On your gas tank I would look for a used one and replace it. I know I have seen two different C's being parted out with parts for sale on Craig's list in Michigan in the last few weeks.

JK-NY · Jan 12, 2013

Is it leaking? If so I would look for another tank.If not maybe you could use fiberglass (Bondo) to fill the dent if you cant use it as is. If you want to try saving that one, maybe fill it with water and let it freeze and see if the expansion pushes it out some then use fiberglass.Put the dent towards the bottom.May be cold enough by the end of next week for that . Be very careful if you go to heating/welding/drilling etc as mentioned below.

How to pop a dent out of a gas tank?

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Similar threads