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Tank / Diff clearance

Discussion in 'Builds and Fabricators Forum' started by Rich M., Mar 8, 2015.

  1. Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

    For you guys that have done the rear tank mod. What is an acceptable tank / diff. clearance? I have a flatfender glass tub on an ECJ5 frame. The frame will be bobbed a a few inches in back so it looks like I'll have to move the crossmember forward to squeeze the 72 tank in. Second thought is to just flip the crossmember around and notch the bottom. Diff clearance looks like it will be tight 1.5" +/- Thanks!
     
    Rich M., Mar 8, 2015
    #1
  2. n6ifp

    n6ifp Member

    I don't believe I have any more than the 1.5 inch of clearance in mine. I do have an aftermarket tank and I do have to work at getting up and in. Never had a problem with it hitting diff.My rear cross member is in stock location with1969 steel body.
     
    n6ifp, Mar 8, 2015
    #2
  3. Warloch

    Warloch Did you say Flattie??? Staff Member

    Articulation my friend - that is the key. I had a rear tank in my rig for several years, swapped springs and the first trip it split the bottom of the tank out as the 3rd member rotated into it.

    Clearance and needs when it's that close to the axle is dependent on your articulation. You can then limit it with bump stops if needed. I build my own tanks now, and the last one even has a notch out for 3rd member clearance.
     
    Warloch, Mar 9, 2015
    #3
  4. mpc

    mpc Member

    I had poor clearance with the tank I put in so I recessed it up into the bed by 4" then built a new frame for that section of raised floor. It steps back down under the rear seat, so it's hidden pretty well.
    Even with that my rear diff will still occasionally bump the tank skid plate on a hard drop. I also had to move the cross member forward to fit the tank.
     
    mpc, Mar 9, 2015
    #4
  5. metal_miner

    metal_miner New Member

    Warloch-
    What are the dimensions of your tank? Do you set them up to pull fuel from the bottom or through a sending unit out the top? Do you have any pictures you can post by any chance? -Thanks-
     
    metal_miner, Apr 17, 2016
    #5
  6. Warloch

    Warloch Did you say Flattie??? Staff Member

    I'd have to go measure them as I don't see them in the book here (could have sworn I did).

    To the other items. All my tanks are plumbed to run from the top, Pickup tube, tank Baffles, Sending unit, return line, vent on the ones I build. Seriously considered a drain, probably should have done that as well and will for the next one.

    You can see some of the tank for the Blue '49 on my site (warloch.com), I'll get some pics when I do measurements and post them.
     
    Warloch, Apr 18, 2016
    #6
  7. metal_miner

    metal_miner New Member

    Dumb question: How much does the rear axle swing to the rear on spring compression if it's fixed on the front mount? Just the length of the shackle?
     
    metal_miner, May 27, 2016
    #7
  8. tarry99

    tarry99 Member

    All will be a little different depending on suspension...........look at your drive shaft slip yoke........the wear lines should give you a good Idea how much it's moving.......normally less than 1" but nothing is normal!
     
    tarry99, May 27, 2016
    #8
  9. Warloch

    Warloch Did you say Flattie??? Staff Member

    And I forgot about this with a parent health issue... I'll do it while out in the shop this weekend.
     
    Warloch, May 27, 2016
    #9
  10. Warloch

    Warloch Did you say Flattie??? Staff Member

    I have two designs I used - first was not as simple and has some shape to clear the rear diff - I can draw something up if you want, but here is the basic
    Width is 23"
    Height tapers Rear is 10.25" for 13" angles up to meet flat 4" tall section for last 5.25"
    Depth on top is 22" from rear to front

    The last one is 23"W x 17"D x 11.25"T and has a notch area for diff clearance.
     
    Warloch, Jun 1, 2016
    #10