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Should I Go With Cj-5 Tank?

Discussion in 'Early CJ5 and CJ6 Tech' started by Tom Z, Oct 20, 2019.

  1. Oct 20, 2019
    Tom Z

    Tom Z New Member

    Surfside, CA
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    My CJ-5 vs M38a1 dilemma continues (intro thread): drive train is CJ-5, body is M38a1 (mostly).

    After a few weeks of being too busy to do much on the Jeep I decided I needed to pull the fuel tank and replace it. Luckily I did the pulling before the buying. I've attached an image of the pulled tank. I could attempt a treatment, but there is a ton of sealant already in the tank that is chipping off due to rust underneath.

    Aside from condition, this tank doesn't match up with any M38a1 tanks I can see for sale. Prev owner drilled a 6-hole pattern around the 5-hole on the tank. The small hole had a long fuel line soldered to the tank (not welded).

    Going off measurements, it seems a CJ-5 tank should "fit" under seat no problem (may need new floor pan and filler neck housing). Anyone with more experience than me (just about everyone) have advice?
     

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  2. Oct 20, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I don't know why a CJ5 tank wouldn't fit if you fix the floor as suggested.
     
  3. Oct 20, 2019
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    Welcome from Michigan. I have a 1964 CJ 5A, Civilian Model, Small hole in the body for the regular tank. When I re-constructed my Jeep I wanted a brand new tank, just to know it was safe. I bought a plastic tank thought it would be better than metal, the neck was off center in the filler hole in the body. I was able to exchange it for a metal tank and it worked out good for me. My Jeep has a gravity feed to the fuel pump, so the line hooks up to the bottom of the tank, no suction line on top, so it was easy to install. I like my under the seat gas tank, everything is new, there is no gas smell inside the Jeep. Just a suggestion, I spaced my tank a little off the floor with shims, about 3/16" so I get air flow to dry any water out, and I can clean out from under the tank with a blow gun, just something to consider, Good Luck.
     
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  4. Oct 20, 2019
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    Not "may"....."will"
    The CJ filler neck is much smaller, and the tank is flat on the bottom it doesn't have the dropped down section.
     
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  5. Oct 21, 2019
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

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  6. Oct 21, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Replacement M38A1 tanks are expensive. But when you consider it would be a drop-in fit, and good for decades to come, it might be the best choice.

    They can be found cheaper than the KaiserWillys price. Willys JEEP M38A1 1952-1966 Fuel Gas Tank MFS004 | eBay

    Swapping to a CJ5 tank would still require expenditure, and working out the modifications. With the military tank besides saving time and trouble, you will have a much larger capacity than a civilian tank.

    As an added bonus, the extra large filler neck allows you to drop a hand grenade into the tank, should you need to prevent the enemy capturing your jeep.

    Or possibly you could tumble the crap liner out of your existing tank, recondition it, and try to reverse the PO's modification. I spent a lot of time soldering about a hundred rust-holes in mine, rather than buy a new one.
     
    Last edited: Oct 21, 2019
  7. Oct 21, 2019
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    If your tank well in your M38a-1 body is in good shape rust/dent-wise, You are ahead of the game! Do you have any old-fashioned radiator shops around that can boil out the lining and rust on your original tank? The original tanks were really well made, and I would try to see if its salvageable. I much prefer the larger tank if possible. I have a custom aluminum tank for my M38a-1 body, made by a boat tank welder.
    If you end up getting a CJ5 tank, you can cut down a treated wood 2x4 and make one or two "stringers" to set in the tank well (parallel to the rocker panel) to support a civvy gas tank. I did this for years and it worked fine. I made a heavy rubberr boot around the smaller gas filler to fill in the gap in the diameter.
    -Donny
     
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  8. Oct 21, 2019
    kenb

    kenb Cleverly disguised as a responsible adult

    Detroit
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    I didn't realize that was an option but even so I'm not sure I can run fast enough to make that work.

    For the OP, I would stick with an M38A1 tank if possible. It's correct, it fits your tub better, it has extra capacity, you feel really macho at the gas station when you remove that big filler cap.
     
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  9. Oct 21, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Destruction with explosives is covered in section 289 of the FSM (military Operations Manual).
     
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  10. Oct 21, 2019
    scott milliner

    scott milliner Master Fabricator

    Seattle Wa.
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    I had my M38a1 tank fixed, cleaned and lined both inside and out by a radiator shop.
    The problem with M38a1 is dirt gets down into the floor well and rusts the bottom of the tank. My original tank rusted though. Found one at a swap meet that I have in iit now.
     
  11. Oct 21, 2019
    Tom Z

    Tom Z New Member

    Surfside, CA
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    I actually considered this as a way to get some under-seat storage.

    The tank seems fine externally, no rust holes. The floor pan has some iffy spots though.

    I will see if a local shop can do it for cheap. $450+ for a new tank is a little outside my budget for the get-it-road-legal phase of the project.

    Thank you everyone!
     
  12. Oct 21, 2019
    Mike C

    Mike C Member

    Austin, TX
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    I bought the new tank for my A1. My original was not useable. It was painfully expensive, and I am really glad I did it in hindsight. My A1 has been together for 10 years now and that helps spread the pain out over time!
     
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  13. Oct 22, 2019
    gunner

    gunner Member

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    I couldn't finish that section of the manual- way too sad!

    My A1 tank had many pinholes when I bought it. My first job as a kid was driving for an old school radiator shop, picking up and delivering to dozens of shops in Dago. Saw many a gas tank cleaned and repaired, so knew I might be able to repeat that with my A1 tank. Sure enough, found a pretty old school radiator shop on the mainland. They cleaned it, did some fiberglassing and sealed the inside with some sort of a blue compound. It's held beautifully for 10 years now. Cost about $150 and well worth it. So, try to preserve the tank.

    By the way, there are not many true radiator shops around anymore. The one I went to specialized in big radiators- picture the ones coming out of rigs with big diesel engines: OTR rigs, dump trucks, tenders, etc.
     
  14. Oct 22, 2019
    Tom Z

    Tom Z New Member

    Surfside, CA
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    There are still some old school shops around me here in southern California. I'm not too far from Stanton, CA and there are tons of auto specialists there.
     
  15. Oct 23, 2019
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    Welcome from Michigan, Tom.
     
  16. Nov 8, 2019
    dieseljeeper

    dieseljeeper New Member

    spanaway, wa
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    If you are set on a cj5 tank, Willys used the same floor pan in cj5 as m38a1 with a sheet metal piece spot welded in place of the tank well. On the other hand replacement wells are readily available from Midwest Military and the tanks are made fom heavy enough metal a new bottom can be welded in pretty easily. One other thing I would consider is undo the stand pipe set up the op put in and put the fuel distribution plate back in as thats how the tank vents
     
  17. Nov 9, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    The military set-up also has the advantage of an in-tank fuel filter.
     
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