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35's Front End Shimmy

Discussion in '40- & 55-Series Tech' started by sambudo, Jul 13, 2003.

  1. sambudo

    sambudo

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    At 50 + the front end shacks really bad. 2.5 shackles w/SUA. I thought tire pressure! Any suggestions to look at, and possible remidies to fix it? It shacks in a bad way! Thanks for the help!
     
  2. 3_puppies

    3_puppies SILVER Star

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  3. CruisinGA

    CruisinGA

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    Did you shim your axles when you installed the longer shackles?
    I might be taking a shot in the dark but I think these can be related.
     
  4. hammerhead

    hammerhead

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    check tire balance, all steering rod ends, alignment, shocks, spring bushings, and stabilizer if any. What steering setup are you running?
     
  5. sambudo

    sambudo

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    Tires are balanced, tie rods are in fair condition. Steering stabilizer I am not sure of, center arm is going out and in need of replacement. I have stock manual steering.

    [attachment deleted by admin]
     
  6. hammerhead

    hammerhead

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    35s caused mine to wiggle at first too. It seems to like a hair under 1/8" of toe-in. Also, a tie-rod mounted stabilizer made a big improvement both on the hiway and in the rocks(in rocks your hands will thank you). The stock steering has a reputation of being "sloppy". There are some adjustments that can make a huge difference.
    First, the box is just like any, a locking nut on an adjuster screw. Loosen nut, adj. screw, tighten nut.
    Second, the pivot or bellcrank is adjusted in the same fashion.
    Third, the steering rod from the box is also adjustable, although not as well known. At the end of the rod you will find a cotter pin retaining an adjuster. Remove pin, tighten screw till it bottoms out, back out screw approx. 1/4 turn to line up slot, install new cotter pin.
     
  7. sambudo

    sambudo

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    Thank you, I will check these things out to night! hopefully this will help.
     
  8. hammerhead

    hammerhead

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    D'ya try those adjustments yet? They may help driveability while you're working towards power steering. You still may want the stabilizer even with power steering so it won't be wasted to install one now.
     
  9. woodchuck

    woodchuck

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    Hey Sambudo,
    My rig did the exact same thing until last night (I also run 35" tires). Actually my shimmy started when the speedometer read 50, although I was probably doing 60+.
    I had replaced all of the tie rod ends, rebuilt the knuckles and just got power steering installed. Still did it.
    CruisinGA nailed it on the head. 2deg shims for the rear. NO vibration accelerating or decelerating at the higher speeds. What a difference.
    Make sure when you install them that the fat end of the wedge goes back, towards the shackle. The idea is to tip the pinion "down".
     
  10. hammerhead

    hammerhead

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    Good call Woodchuck, I'd forgotten about steering angles because I welded my perches on with 4 1/2 degrees figured in (advice from another TLC fanatic).
     
  11. sambudo

    sambudo

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    what do you mean by shimming the rear axles? Where do you do this? I made a few adjustments to the center arm and tie rods. CR needs to be replaced. I do plan on doing p/s soon, and didn't want to have an expense to fix, and then another one to change it.

    I drove iton the hwy and it seemed a lot better, not corrected as of yet. So if your speedo shows 50, you are probably doing 60? Is this correct?
     
  12. CruisinGA

    CruisinGA

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    [quote author=sambudo link=board=1;threadid=3633;start=0#msg27394 date=1058421987]
    what do you mean by shimming the rear axles? Where do you do this? I made a few adjustments to the center arm and tie rods. CR needs to be replaced. I do plan on doing p/s soon, and didn't want to have an expense to fix, and then another one to change it.

    I drove iton the hwy and it seemed a lot better, not corrected as of yet. So if your speedo shows 50, you are probably doing 60? Is this correct?
    [/quote]
    By "Shimming" we mean taking a wedge-shaped piece of metal and installing it in between the spring pack and the axle perch on the axle. This corrects pinion angle to be like it was before the extended shackles and on the front, it corrects some steering angle issues. Sor sells them. There is a formula to determine what size you need. Pin Head posted it awhile back. Search around and see what you come up with.
     
  13. woodchuck

    woodchuck

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    Yeah, like CruisinGA posted, SOR sells them. I picked mine up at NAPA. They are run of the mill steel wedges. One thing to note, SOR has pictures that are incorrect. They show isntalling the wedge with the fat side forward, toward the transfer case. The wedge needs to go in with the fat side towards the shackle.
    This was discussed more in depth on past posts. If it wasn't on this website it should be in the SOR archives.
    As far as the speedo being off, I haven't clocked off the miles to determine how far off it is. I keep up with traffic when mine reads 50, just a guess that I'm doing 60. I'm not worried about breaking many speed limits in this rig.
     
  14. sambudo

    sambudo

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    i know what you mean about the spped. Probably get a ticket for going to slow! I will check out the shims. And do some more reading through the archives.
     
  15. erfworm

    erfworm

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    If you had the springs off recently, I would check the torque of the u-bolts. If they are o.k. then go ahead and give them all some snugging. Those pesky things always like to loosen up untill there is a good amount of crud and rust on them. This took away my shimmy...2.5SUA and 35s, worth a shot. ??? :D
     
  16. hammerhead

    hammerhead

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    Hey Sambudo, Did you beat that wobble yet?
     
  17. sambudo

    sambudo

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    Yes, it works a little better! But still have a slight shimmy! But it works well, I wheeled it hard this weekend, and it performed well! Powersteering is in the works, next month or two.
     
  18. hammerhead

    hammerhead

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    Sambudo, have you corrected your steering angles yet?
     
  19. hammerhead

    hammerhead

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