Advice On Fuel Tank

I think this under seat fuel tank is stock.
Sending unit seems to be stock, it’s still in good shape, even the cork float! The resistance checked out on a bench test. Not so sure about the plumbing on the bottom.


There is some pretty bad/deep pitting on the sides and bottom, large pieces were coming off with a simple wire wheel.


Having never dealt with a fuel tank before, I’m looking for advice - is it worth it to sandblast and paint one with pitting like this, or am I better off just replacing it?

 

Try a non vented cap and light pressure. If you have a livestock water trough and sandbags toss it in under pressure and check for leaks.
FWIW my tank had hemmed ends like a jerry can and not welded corners that makes me think yours might be a little thicker material.
Most importantly is the amount of rust inside the tank. If the inside is crud it's not worth the effort on the outside.

 

new steel tanks are available from online vendors.I put one in my '69 cj5. I would not mess with that tank if I planed to drive it or have it sit in my garage and start leaking and cause a fire. Not worth it.I ordered a plastic tank and after I laid eyes on it back it went. mike

 

The deep rust pocking looks rather suspicious, otherwise if looked pretty decent externally.
So try doing a low pressure test as Joe mentioned.
Internal rust is very troublesome but varnish buildup is an easy fix.
The original tanks are a much better fit most every time.
Save the send unit for sure.

 

Mine too. Were welded tanks OEM?


Investigate the pits aggressively, even try to make a hole. If there is any weak point, better to find it now.

That said, I have repaired such tanks with soldering. But you need to be thorough about it - gas will find the tiniest flaw, and you don't want to be doing everything twice.

Then give it a good paint job to prevent future rust.

 

I’ve installed several MTS tanks. Never had an issue. Definitely not for a restoration project though.

 

You may try to coating the inside with POR-15. I’ve salvaged some Jerry cans that way. It does a great job sealing any pinholes.

 

I would sandblast (lower pressure) the bad rust areas. I wouldn't be suprised if some spots were to blast through. Soldering is easy if the metal is spotless from blasting, provided any holes are 1/8" or less.
I always keep the tank fully vented (cap off) and usually 3/4 full of water. Blasting causes sparks.
Original tanks have a heavy tin coating inside that aftermarket tanks don't. I prefer to salvage originals for their quality.
-Donny

 

Thanks everyone, lots of good advice.

I think I'm going to gently blast this one and take a real close look at maybe soldering up some of the bad parts and try to save it. It looks really clean inside, a light grey color. The seams around the edges are welded and look to be very thick welds.

What about the plumbing on the bottom - Does anyone know what should be there versus what was added by a PO?

 

It's been a while since I sized the fittings on mine but I recall a 1/2" npt with a plug for the drain and a 3/8 npt with curved tube on the inside for the pickup that had a npt to flair elbow. I wouldn't worry about stock because it never pulls to empty and there isn't much in a 10gal tank to start with.

If I were making a tank I would put a small sump inboard rear with the drain and petcock.

 

The normal outlet fitting were steel that was soldered into place.
Looks like yours was possibly welded on and could easily be soldered or better yet brazed if need be.
Of course brazing or welding will require you to purge out all the tank fumes

 

I always thought you were supposed to fill it up with 87 octane before welding?

Just kidding, it’s been bone dry stored inside open to air for 16 months.

I’m not doing a restoration as much as I’m just trying to go through and undo just about everything that the POs did on the farm in Idaho where this Jeep slowly disintegrated and was repaired with whatever was around.



edit: I actually took a closer look inside with a light and see some rust. Not good right? Here’s a closeup:

 

Light internal rust could be removed with that stuff that Eastwood sells.
Should be much safer to use than muratic acid.
I certainly would not trust any air dried tank.
Test all tanks for fumes by positioning tank around corner of a solid wall.
Reach around corner with long oxyacetylene flame going direct into the tank opening.
No boom = good to weld on.
The last gas tank I messed with was about a month ago.
Was an old Jeep tank that sat open for well over 10 years.
Tested as described.
No boom !

 

1956 tank has an outlet with 1/4" inverted flare (fits standard brake tube fitting) and a pipe thread drain plug.

 

I pretty sure all original tanks had two outlets on the bottom. The supply line to the fuel pump was an inverted flair fitting/hole and was flush with bottom of tank. The drain hole/fitting was an 1/8 inch pipe thread and was in a recessed area two or three inches from other hole. Yours looks like an old reproduction tank anyway. I just cleaned the inside of mine with an acid etch and degreaser and sealed it with Bill Hirsch's tank sealer tank kit. Had several rust holes in it and closed them up with an epoxy mix , then used the tank sealer. sloshed it around and poured out excess and let it dry a few days. Several months with tank full of gas and no leaks! Bill Hirsch's tank sealer kit is designed for the alcohol fuels we use today and doesn't break down like some do. Check their website. Painted outside with POR-15 Gloss black.

 

As I recall POR needs a topcoat to protect it from UV. At least back when I last used it.

 

Anyone know the answer to this? My tank is definitely welded and I'm starting to wonder if it's in the category of all the other stuff the POs added along the way.

 

All the original ones I’ve seen were crimped at the seam. No welds unless repaired.

 

Thanks. I guess this gets added to the list of replace instead of repair then.



Are there any other new US-made options (besides overseas, Crown or Omix) for steel replacements?

 

That is definitely not factory. Not sure on steel replacements but I recall this being discussed in the past. Hopefully Someone will chime in but also might do a search.