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Front Shackle Question

Discussion in 'Intermediate CJ-5/6/7/8' started by VonBergmann, May 3, 2020.

  1. May 3, 2020
    VonBergmann

    VonBergmann New Member

    Camarillo, CA
    Joined:
    Mar 24, 2020
    Messages:
    11
    Hi all,

    Still working on improving the steering on my 72 w 304. A new steering box helped tremendously. The PO did a very clean install of a 2.5” medium duty OME YJ spring conversion. The new shackles he installed look pretty long to me. As in 5 1/2” center bolt to center bolt.

    Would shortening the length have the possibility of improving the steering? Would that effect the stance/ rake of the Jeep? I know everything effects everything, so i guess I am looking for a general answer, and any recommendations the group may have. It has 31s and will be doing mostly paved and fireroad duty. I really appreciate this forum. Thanks so much.
     
  2. May 4, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
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    6,656
    General answer, yes.
    Shorter shackles would lessen the pendulum effect of the axle as lateral forces (like steering) are put upon it. The longer the shackles are, any play in the bushings is multiplied.
    Also, if the shackles are still up front, shorter shackles will improve you caster angle by a little bit, helping it track straighter.

    Every inch you shorten the shackles, you’ll lose 1/2 inch in ride height.
     
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  3. May 4, 2020
    Sierra Bum

    Sierra Bum Member

    The High Sierra
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    Oct 23, 2017
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    329
    Sorry to be redundant...I was typing while the above post came in....

    What steering issues are you having? 5.5" long shackles seems kind of long. Can you post pictures of the set-up? Reducing shackle length some should improve your steering depending on how things are currently set up. With the spring lift and longer shackles I'd expect your caster angle to be off a bit if it was not already compensated for.

    Does your steering wheel return to center on it's own? Does the Jeep wander around a bit at highway speeds?

    With a reduction of shackle length, you will lose 1/2 of whatever you subtract in lift. For example, moving to a 4.5" shackle will yield a loss of 1/2" in lift. This will however help in restoring a proper caster angle (5-7 degrees positive caster).

    It's also worth checking toe-in.
     
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  4. May 4, 2020
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Southern...
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    Nov 24, 2019
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    That is a very general question. However I would say 5.5 inches is a bit much. long shackles tend to lean or twist more easily without a tracking bar. Shorter shackles should lower the jeep some improving any bump steer you might have. Also it should slightly improve axle caster( positive) which would increase drive-ability or return to center. what angle are your shackles at with the jeep weight on them now? post some side view pic. Norcal 69 has a lot of experience with this maybe he or some of the other guys with lift spring experience could help.
    sorry for being redundant as well I was watching tv and typing at the same time.
     
    Last edited: May 4, 2020
  5. May 4, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    Have you measured the steering geometry? If you go to a local shop for alignment, they can set the toe-in and center the steering without any heroic measures. You should ask for the printout from the alignment machine. This will tell you the caster and camber of the front axle. Caster makes a big difference to drivability, and can change a lot with the kind of mods you describe.

    As above, longer shackles changes the caster and the ride height.
     
  6. May 5, 2020
    VonBergmann

    VonBergmann New Member

    Camarillo, CA
    Joined:
    Mar 24, 2020
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    11
    Thanks for the reply everyone. I know this is a rookie question, and I know there are a ton of threads, but the help is much appreciated.

    Regarding geometry, I have not done an alignment as my alignment guy said it would be better to change the shackle before I do the alignment. That makes sense to me so I don't have to do two aklignments.

    Also, the floor to the bottom of both front and rear shackles is 17". Would shortening the front shackle My aligmnment guy said that would not mess w having a level ride height. For what it is worth, he has 30 years of doing front ends at his one man shop, so he is not a rookie.

    Here are some pics. Thanks again for the assistance.
    Mel IMG_7437.jpeg IMG_7436.jpeg IMG_7435.jpeg IMG_7434.jpeg IMG_7432.jpeg IMG_7433.jpeg
     
  7. May 5, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    I think something was lost in translation there.
     
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  8. May 5, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Your alignment guy is right to pick the shackle length you want before you measure the alignment. You are pretty much putting the cart before the horse to ask about the steering quality before the alignment is measured and set.

    Suggest you read the above posts again. Changing the shackle length will change the ride height.

    There is not much upside to long shackles. You can make them an inch or two longer than factory length and get a little more ride height. Usually very long shackles are installed as a half-a** way to get some lift cheaply, instead of doing it right and buying the proper springs. Really, you don't need a lot of lift with a CJ.

    Caster and camber are welded-in to the axle. Lift springs and long shackles will change caster, typically in the wrong direction for steering stability. Both caster and camber are corrected by adding shims. To add caster shims, the axle has to come off of the springs. Talk with your alignment guy about this.
     
    Last edited: May 5, 2020
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  9. May 5, 2020
    Sierra Bum

    Sierra Bum Member

    The High Sierra
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    Question: Are your shackles the same length front and rear?

    If your rig is level now....Going to a shorter shackle (the same amount shorter) front AND rear will maintain a level stance.
    However...shorter in just the front will drop the front a little making the rear higher.
    Personally I’d aim for 3.5”-4” off center hole to hole shackles, install, measure for caster, then adjust with shims if necessary.
    There’s lots of guys here with YJ springs who have it figured out...maybe ask what they’re using.
     
    Last edited: May 5, 2020
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  10. May 5, 2020
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Southern...
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    x2 exactly,
     
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  11. May 5, 2020
    bigjohn

    bigjohn Active Member

    Kelso Wa
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    On a different note, that shackle angle looks very wrong. Like the top mount is too far forward. Is it me or the angle? The shackles should be slightly forward at the bottom bolt compared to the top. Is all the weight on the jeep in the latter photos?
     
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  12. May 6, 2020
    VonBergmann

    VonBergmann New Member

    Camarillo, CA
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    Mar 24, 2020
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    Thanks again for all the feedback. Sierra Bum, Appreciate your view. I will report back when I get to do some work on it. Thanks again.
     
  13. May 8, 2020
    Mountain Goat

    Mountain Goat New Member

    Rocklin, ca
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    Oct 5, 2019
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    I run 5" shackles on my jeep with 2.5" YJ springs and have another bolt hole in my shackles between the spring and frame mounts i have a sleeve and bolt through there this helps from keeping them from flexing, but as mentioned above long shackles are much harder on bushings. Your shackle angle does seem weird in that image you want them slightly raked forward. Mine sit at 40-45 degrees. It may be the image, but yours seem straight up and down. UNADJUSTEDNONRAW_thumb_26cb.jpg UNADJUSTEDNONRAW_thumb_26cd.jpg
     
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  14. May 11, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    Apr 27, 2017
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    326
    Looks like the previous owner used the Rocky Road YJ Spring conversion kit. This kit generally seems to work well. I wouldn't worry about the shackle angle for now, but I do agree with going to a 4" c-c shackle before doing the alignment. Your alignment guy can fix the rest with a set of degreed shims between the axle and the leaf springs.
     
  15. May 13, 2020
    scott milliner

    scott milliner Master Fabricator

    Seattle Wa.
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    Dec 17, 2002
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    My Rocky Road shackles are only 3 1/2" long. I also have the heavy duty 3 1/2" lift spring. My angel is 65 degrees, after the spring settle. I agree with John. I have seen RR YJ conversion front shackles invert on axle drop. This how ever has never happened to me.

    [​IMG]
     
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