How to clean out gas tank

[Austin]

First, is it possible and if how so, how? I have my gas tank off the jeep and wanted to make sure it's clean inside and out before putting back on. Can I just spray a cleaner in there an let air dry?

Here a picture I snapped of the inside
View attachment 10756

Here is the outside of the tank
View attachment 10757

 

[PaRenegade]

If your not going to paint the interior with a liner of some type, the rust will come back. Have you looked into a poly tank? I went thru 2 steel tanks before I went poly and no more problems in 18 years.

To clean your tank, take a short length of chain and stick inside, then shake, shake, shake, your butt off. Dump it. Then take metal etch and etch the tank according to directions. Rinse out with warm water and allow it to dry. (torch to outside of tank usually helps) Then line it. Most tank liner products come with cleaner, etcher, and liner.
I have successfully used Kreem brand tank liner kits on a 26 gal pickup tank and 2 motorcycle tanks.

 

[hole]

On old military truck tanks we just put some gravel in and then strap the tank to a cement mixer and let it spin all day. Not too big of rock ought to work for a CJ tank.

 

[Austin]

If your not going to paint the interior with a liner of some type, the rust will come back. Have you looked into a poly tank? I went thru 2 steel tanks before I went poly and no more problems in 18 years.

To clean your tank, take a short length of chain and stick inside, then shake, shake, shake, your butt off. Dump it. Then take metal etch and etch the tank according to directions. Rinse out with warm water and allow it to dry. (torch to outside of tank usually helps) Then line it. Most tank liner products come with cleaner, etcher, and liner.
I have successfully used Kreem brand tank liner kits on a 26 gal pickup tank and 2 motorcycle tanks.

Thanks for the info. I have looked at the poly tanks and really do like them. Were most 76-86 CJ's 15 gallon? I was looking at the 15 gal poly tank but then also noticed they have a 20 gal.

 

[Torxhead]

Austin, everything is give and take. The poly tanks will not rust, but theres always something that can get thru the filters at the gas pump. The later oem CJ tanks were 15 gal. with a 20 gal. option. I am not sure how a poly tank will do in the rocks, but that depends on what kind of driving you do. The 20 gal. does hang down a bit more also, so take your pick.

 

[hole]

I put a 21 gallon poly in mine, and it's about 3 1/2" lower than the stock 15 gallon tank. Before I lifted my 8 the rear diff would rub on the tank mount/skid plate on rough terrain.

 

[Saddle Tramp]

Remember one of the most important parts to the gas tank/skid plate system is the foam pad between the bottom of the tank and the skid plate to prevent rocks from becominglodged between the two and puncturing the tank.

 

[Austin]

I ordered a new steel 15 gal tank today. I was trying to clean out the other one and noticed the fuel pick up lines had basically crumbled. Picked up a new fuel sending unit, lines, filter and hoses as well. Any suggestions on a good coating I can put on the steel tank to keep it from rusting? I picked up por-15 for all the other metal parts?

 

[PaRenegade]

Sorry I didn't reply sooner. I've been on vacation this past week. Yes I would use POR on the tank and the skid. Saddletramp mentioned about the foam pad, mine was a plastic piece shaped like the tank bottom half; being important to use and I agree. The down side is that it can trap water and rust the tanks bottom. This is what happened to my first 2 tanks before I switched to a poly one. So paint it well. And yes mine was a 15 gal. one. I didn't spring for the 21 gal. option initially so I'd have had to get a new skid plate also.

 

[FiNorman]

Sorry I didn't reply sooner. I've been on vacation this past week. Yes I would use POR on the tank and the skid. Saddletramp mentioned about the foam pad, mine was a plastic piece shaped like the tank bottom half; being important to use and I agree. The down side is that it can trap water and rust the tanks bottom. This is what happened to my first 2 tanks before I switched to a poly one. So paint it well. And yes mine was a 15 gal. one. I didn't spring for the 21 gal. option initially so I'd have had to get a new skid plate also.

I have the 20 gallon plastic tank... I dropped the tank, cleaned the metal skid plate container, painted the outside of the skid plate and cleaned the outside of the tank.

I have noticed inside the tank there is a significant amount of dirt, rust and debris.

Do you have any suggestions on what I should use to clean the inside of the tank? Can I use the same method you used for the metal tank and maybe rinse with brake cleaner? thanks.

 

[PaRenegade]

I would find a cleaner, such as POR's MarineClean, that mixes with hot water and slosh that around real good. Then set it in the sun with the holes up to let it dry.

 

[danray48]

If your not going to paint the interior with a liner of some type, the rust will come back. Have you looked into a poly tank? I went thru 2 steel tanks before I went poly and no more problems in 18 years.

To clean your tank, take a short length of chain and stick inside, then shake, shake, shake, your butt off. Dump it. Then take metal etch and etch the tank according to directions. Rinse out with warm water and allow it to dry. (torch to outside of tank usually helps) Then line it. Most tank liner products come with cleaner, etcher, and liner.
I have successfully used Kreem brand tank liner kits on a 26 gal pickup tank and 2 motorcycle tanks.

I took a tractor tank to a radiator repair shop one time, and they poured a liner rubber type stuff in my tank worked great. But not to start an argument, I would never take and put a torch of any kind on the outside of a metal tank. I dont care how much you wash it out, they still hold fumes, and they have and can go boom.

 

[PaRenegade]

After it was washed and etched any trace of gas should be gone or it wasn't done very well and the liner won't stick.

 

[1986cj7]

I took a tractor tank to a radiator repair shop one time, and they poured a liner rubber type stuff in my tank worked great. But not to start an argument, I would never take and put a torch of any kind on the outside of a metal tank. I dont care how much you wash it out, they still hold fumes, and they have and can go boom.

Never use a torch on any kind of fuel tank. I friend of mine does a lot of welding and he says that the gas can soak into the metal and no matter how much you wash clean what ever it can still blow up. He said the only way to weld or torch a tank is to fill it with dry ice and then it is still iffy. He always tells the owner no, to either buy a new tank or find someone else to do the job.

 

[PaRenegade]

I think your confusing fumes with smell. Smell isn't flammable or explosive. Fumes are, but come from liquid gas, of which there would be none. There would have to be a lot of fumes present to ignite, and if there were it still wouldn't explode because there would be 5 holes open and no pressure could build to explode. It would be more of a flash puff.
I also don't buy that the metal would soak up any gas. If it did they wouldn't use metal tanks. But lets say it would get into the surface pores. The etching acid would open those up and the etching solution (usually added to hot water) would wash them away.
Come on guys, if gas were that volatile that even minute traces could produce fumes in explosive quantities, we wouldn't be using gas as commonly as we do.

 

[Saddle Tramp]

Sorry I didn't reply sooner. I've been on vacation this past week. Yes I would use POR on the tank and the skid. Saddletramp mentioned about the foam pad, mine was a plastic piece shaped like the tank bottom half; being important to use and I agree. The down side is that it can trap water and rust the tanks bottom. This is what happened to my first 2 tanks before I switched to a poly one. So paint it well. And yes mine was a 15 gal. one. I didn't spring for the 21 gal. option initially so I'd have had to get a new skid plate also.

How I know about the foam pad is that Jeep didn’t use one on the 1972 model year. I pulled the tank about a dozen times to braze a repair from small rock damage before I swapped the jeep, and had to keep a bar of soap handy for a quick leak stop while on the trail to get home. Anyway, you need to use something between the tank and the skid plate.

 

[danray48]

Never use a torch on any kind of fuel tank. I friend of mine does a lot of welding and he says that the gas can soak into the metal and no matter how much you wash clean what ever it can still blow up. He said the only way to weld or torch a tank is to fill it with dry ice and then it is still iffy. He always tells the owner no, to either buy a new tank or find someone else to do the job.

You are exactly right. Just how many people out there can tell if it's smell or fumes. Either way, I have always been told never weld, or put a torch on a used gas tank. Dont believe it? Take a used tank to a repair shop and ask them to weld the hole shut. It's like anything dangerous, You might get away with it, and you might not. And yes, gas does get into pores of the metal. If paint can get into the pores of metal to stop rust, why cant gas get into pores?

 

[PaRenegade]

People repair gas tanks all the time by welding in some form. Sometimes they'll blow argon gas or exhaust fumes into it, others just clean it good with soap and water. If you can't tell the difference between smell and fumes, you've probably never experienced fumes.
Paint or gas doesn't get into the pores, it gets into the nooks and crannies of the irregular surface, which is only visible with a microscope. Metal is non-porous. It doesn't "soak up" things. It's irregular surface "grips" things, that's why you rough up a surface before painting it. Look at oil, it seeps thru anywhere. But you can also remove oil completely from a metal surface too.

Look, we're not talking about just any gas tank here. We're talking about a washed and etched gas tank here. Nor are we talking about putting a flame inside of a tank. And if your afraid of touching a torch flame to the outside of a tank... use a heat gun. It'll just take a lot longer and flash rust could occur.

Gas tank repair brazing - YouTube
Davidsfarm 1093 tD4KiQEnxwQ SQ Weld fuel tank with gas in it - YouTube (skip to about 1:30 into it)

 

[BrockGrimes]

Try gas tank electrolysis rust removal:

All you need is a few simple supplies, as for a container big enough.
Use plastic feed/water tubs from tractor supply, or build a box big enough then drop in some heavy plastic like used for landscape/fish ponds. It's cheap if you have the stuff laying around. Rust will be gone!

 

[thiswontbetooexpensive]

Replacement ARBJ670101 Fuel Tank | Auto Parts Warehouse

This link is to a replacement tank for $91. It states that it fits the same year model as the OP owns.

Then they can try all the cleaning, welding, internally coating, electrolysis, waving of voodoo dolls, etc. on their old tank and see what works! Then they can report back and put this issue to bed for us all.