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Original Cj-5 Shackles: U-bolts Vs Plates

Discussion in 'Early Jeep Restoration and Research' started by Peter Dorey, Aug 25, 2021.

  1. Aug 25, 2021
    Peter Dorey

    Peter Dorey Member

    Vista, CA
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  2. Aug 25, 2021
    PeteL

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

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    Early CJ5 had U-type and reversed shackle, same as military.

    But as a side note, the M38A1 had the U-style and plates on the open ends.
     
  3. Aug 25, 2021
    Peter Dorey

    Peter Dorey Member

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    Omix also lists these as fitting 55-75 CJ-5's.
    OMIX 18270.15 Shackle Kit for 55-75 Jeep CJ Vehicles

    So is it highly plausible that my 56' originally ran U-bolt shackles then?
    I am not trying to go back to 100% stock, I am just curious at this point.

    Thanks Pete.
     
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  4. Aug 25, 2021
    PeteL

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

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    Definitely - that was OEM.
     
  5. Aug 25, 2021
    Peter Dorey

    Peter Dorey Member

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    So, when did Jeep switch to plate shackles on the CJ series?
    I just finished installing new suspension on the family Jeep so I have no interest in reverting, but I love the historical knowledge available here!
     
  6. Aug 25, 2021
    oldtime

    oldtime oldtime

    St. Charles,...
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    Cj5 began using the conventional type shackle design in lieu of the “u” type design by 1958 (and possibly as early as 1957 ?)
    Cj3B mainly stayed with the “U” type design with changes toward the conventional design “Silent Bloc” shackles in 1963.
     
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  7. Aug 26, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Just a comment - the aftermarket sellers are often clueless when it comes to application specification. The parts book will help you a lot here. Jeep made mistakes in the parts book listings, but that's in a different universe from the aftermarket listings.

    It's not surprising - the sellers sell parts to make money. They will put little effort into a single part's coverage, especially when the vehicle covered is obscure or few exist. No money in it. No one cares as much about getting this right as you, the owner.
     
  8. Aug 26, 2021
    PeteL

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

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    Amen, Brother!
     
  9. Aug 26, 2021
    Peter Dorey

    Peter Dorey Member

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    the aftermarket sellers are often clueless when it comes to application specification.

    Haha, yeah.... I have a set of useless pedal pads on my shelf that Quadratec said would fit my Jeep. Thanks again guys.
     
  10. Aug 26, 2021
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    If you're concerned about strength don't be- those u shackles are *TOUGH*
     
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  11. Aug 26, 2021
    PeteL

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

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    Yes. The springs will bend first. Don't ask....
     
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  12. Aug 26, 2021
    Peter Dorey

    Peter Dorey Member

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    Howard,

    No concerns with strength. I was told by someone else that my CJ5 should have originally come with plate shackles. I just made a set on my mill and installed them with new bushings and hardware, so I don't have a lot of enthusiasm to undo my handy work at this stage. I just wanted to be right :)
     
  13. Aug 27, 2021
    oldtime

    oldtime oldtime

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    Strength wise; know that the original “u” type shackle can get twisted under severe off road usage. But this occurs rarely enough that I consider it to be of no concern. In fact it should be considered as a desirable weak link in lieu of leaf spring destruction.

    So the military went to a “closed type u” shackle design. I have no experience with those .

    The late cj design is considered to be a conventional “H” shackle design and Jeep referred to them as “Silent Bloc” shackles due to the laminated rubber/steel bushings.
    Here again I think it may be possible to bend the factory bars. The relatively thin and short upright bars could bend sideways under extremely severe usage, but as stated, a weak link can at times be of great advantage to ward off more expensive repairs.
    Today we have the option of installing poly bushings in place of the softer less durable silent blocs. Personally I would shy away from homade shackles with longer bars or thicker bars. An additional cross bar may or may not be of some use ???
     
    Last edited: Aug 27, 2021
  14. Aug 27, 2021
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    When Tonk got boo-boo'd during the teardown I found the U's had a twist in them so I ordered all new ones.

    [​IMG]

    Imagine my surprise when comparing the new with the old that the new had the exact same twist :shock:

    My working theory is that the twist is in there to ameliorate stress forces on the springs arising from axle tilt associated with one wheel going up or down
     
  15. Aug 27, 2021
    oldtime

    oldtime oldtime

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    Exactly. When I said “twist” I was referring to any additional bending beyond the standard form.
     
  16. Aug 27, 2021
    PeteL

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  17. Aug 27, 2021
    Peter Dorey

    Peter Dorey Member

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    Personally I would shy away from homade shackles with longer bars or thicker bars.

    What harm do you see being done by using a thicker bar? I get not using shackles grossly longer than stock, but it seems pretty common for people to replace the OEM shackle plates with stuff that is far heavier.
    FWIW, I went with simple 1/4" CRS bar stock for mine, with 3.000" bolt hole spacing done on my mill.
    [​IMG]
     
  18. Aug 27, 2021
    oldtime

    oldtime oldtime

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    Reversed shackles, very pretty !

    The problem with longer shackles is that they begin to effect the castor and also increase leverage from side sway.
    You actually need slightly less than the standard shackle length to allow the leaves to fully flatten upon full stuff.
    The potential problem with heavier side plates is that you eliminate the suspensions week link; slightly increasing the risk of leaf spring damage.
     
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  19. Aug 27, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Just for interest - this is what they would run, with reversed shackles, on the Jeepster Baja race cars back when I worked at Chuchua's. Apparently very strong.
     
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  20. Aug 27, 2021
    Peter Dorey

    Peter Dorey Member

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    This is the earliest photo I can find of the Jeep, and it appears that the front of the front springs are fixed which means it is likely that the Jeep had factory shackle reversal, but it's kinda hard to make out if thats the spring hanger or the bottom of a shackle hanging down. After reading this thread, it would make sense if it was a factory shackle reversal.

    [​IMG]
     
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