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Rear fuel tank mod problem

Discussion in 'Flat Fender Tech' started by pfmg, Feb 19, 2012.

  1. Feb 19, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    I picked up this tank as I thought it was the one I needed,I believe its from the later 70's cj5. It's about 16.5" deep. Looking at the Willys today, there is not enough room between the rear crossmember and the next one.
    [​IMG]


    I have looked at all the threads here about the mod, and they all look like they fit pretty good.

    Are the dimensions for the early cj 5 and the Willys frame the same back there?


    I think I have the wrong tank??
     
    pfmg, Feb 19, 2012
    #1
  2. Feb 20, 2012
    ErksBurgMN

    ErksBurgMN 200$ Jeep

    Grand Rapids,...
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    Jul 9, 2010
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    The filler neck looks smaller then my CJ5 15gal tank. Maybe this tank you have is an 80's CJ version? The frame widths are identical between CJ2a's and cj5's pre 76, not sure about after 1976. Will this tank fit with out the shield?
     
    ErksBurgMN, Feb 20, 2012
    #2
  3. Feb 20, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    Feb 10, 2010
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    It fits in the frame width, it's the space between the rear crossmember and the next one is where it looks a couple of inches short.
     
    pfmg, Feb 20, 2012
    #3
  4. Feb 20, 2012
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    Didn't notice before but, as mentioned above, that filler neck looks itty bitty compared to mine on the '71. Mot familiar with the later tanks but, I'm thinking this one is for later models. Mine didn't have that tall ring around the SU area either.
     
    wheelie, Feb 20, 2012
    #4
  5. Feb 20, 2012
    rusty

    rusty Well-Known Member

    norfolk,va
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    Yes, that is a 76 and up tank.
     
    rusty, Feb 20, 2012
    #5
  6. Feb 20, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    So for the Willys guys , i guess then. Is there a tank that will fit back there?
     
    pfmg, Feb 20, 2012
    #6
  7. Feb 20, 2012
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Mar 4, 2003
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    I believe the '79 (it's got the larger intake fittings), will fit when you remove the V member. I have been doing the custom tanks long enough that I don't remember for sure (though I had one in a few years ago). I think I still have the tank out in the shop area. It attached at the rear and mid crossmembers.
     
    Warloch, Feb 20, 2012
    #7
  8. Feb 21, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    Does anyone have any measurements to compare with mine. I have 15 1/4" between the rear and mid cross members. That tank in my picture is 16 1/2" without counting the flanged area.

    I would be great if i could find some of these different tanks to measure.
     
    pfmg, Feb 21, 2012
    #8
  9. Feb 21, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    Feb 10, 2010
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    [​IMG]

    The read line is where i have 15 1/4"
     
    pfmg, Feb 21, 2012
    #9
  10. Feb 21, 2012
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Peninsula, Ohio
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    I read somewhere here that someone had an M38 and he moved the crossmember forward the amount of space he needed.
     
    mortten, Feb 21, 2012
    #10
  11. Feb 21, 2012
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I move the crossmember forward when I do my custom tanks. I also put a C channel in the rear for strength first.
     
    Warloch, Feb 21, 2012
    #11
  12. Feb 21, 2012
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    Wouldn't a '70-'75 tank fit?
     
    wheelie, Feb 21, 2012
    #12
  13. Feb 22, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    I heard from a buddy of mine restoring a DJ3a, he measured his tank ( he can not 100% guarantee it is stock) it was roughly 11X15X21 inches, and 10-11 gallons.
     
    pfmg, Feb 22, 2012
    #13
  14. Feb 22, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    after a little quick searching, i found that the 77-83? postal jeep tank is 15-3/4 x 21 x 9-3/4 and is listed as 15 Gal
    [​IMG]



    there is a 10 gallon one, Dimensions: 18 X 15-3/4 X 9-3/4 inches
    [​IMG]
     
    Last edited: Feb 22, 2012
    pfmg, Feb 22, 2012
    #14
  15. Feb 22, 2012
    Vhunter

    Vhunter Member

    Redding, California
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    Howdy, if you are going to build your own tank, here is the formula for calculating the gallons it will hold:

    Hight x width x length x .004329 = gallons
     
    Vhunter, Feb 22, 2012
    #15
  16. Feb 27, 2012
    pfmg

    pfmg Member

    Billerica Mass
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    pfmg, Feb 27, 2012
    #16
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