I broke my wrap bar. need suggestions.

Discussion in '40- & 55-Series Tech' started by dustin, Jun 21, 2005.

  1. dustin

    dustin

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    I built a wrap bar and on the first time out I busted it just by doing a burn out (just did a SOA and 350 conversion). I started the burn out initially in the dirt, and then when the tires caught on the asphault, the bar snapped. I thought the design was pretty solid, but was proven WAY wrong.

    I am trying to get some ideas of how to salvage the main part of the bar and only replace the slip part that mounts to the frame. Clearly the solid stock didnt work they way I had it set up.

    The design uses a slip shaft, and the slip shaft sheeered where I had it go into a sleeve. I had welded the sleve to the slip shaft there as well.

    The main bar that attaches to the axle was 3/16" DOM with a 1" inner ID. Into that slides the 1" piece of solid round stock for the slip shaft. That solid round stock was slid into another sleve on the opposite end and welded together. The sleve was then sleeved again with another inner sleeve that was threaded on the other end of the stock so I could screw in a heim. Basically- the only reason for the sleeve is so I can thread the heim into it. Initially I wasnt going to use a heim, but changed my mind on that later- so some of the pics dont show the heim.

    The shaft broke right where it enteres the sleeve and was welded. I didnt aneal (sp?) the metal, so I hoped the metal wasnt going to be weakened. Guess I was wrong.

    pics:
    The basic pieces. The shaft attached to the plate is bolted in the wrong bolt position in the picture, and I later changed out the mount on the slip shaft to use a heim instead, but you get the idea.
    [​IMG]


    Mount for the front of the bar. I welded the hanger to my t-case mount..
    [​IMG]

    One more showing how it broke. You can see it failed where the solid stock goes into the sleve, at the weld.
    [​IMG]


    I would like to keep the design, but am looking for suggestions on materials to use instead. My heim is a 3/4" heim, so may be overkill. Do you think I could run 1" outter ID DOM and thread in a 5/8 in heim and have it hold up?

    thanks!
    Dustin
    Weekend_work_0024s.JPG LC_final_0004s.JPG LC_final_0008s.JPG
     
    Last edited: Jun 21, 2005
  2. lowenbrau

    lowenbrau

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    Um congratulations?

    You must be making some pretty good power and clearly your bar was resisting a lot of torque. The design seems good, I'd figure a way to heat treat that solid to tube intersection after you weld it.
     
  3. dustin

    dustin

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    congrats on a crappy design :D
    Heat treating that with a rose bud may help, eh?
    Does anyone know if material such as 1" outer DOM would be more resistant to breakage than solid stock? Like, does DOM have a tendancy to deflect more before breaking than solid? I am assuming this was a pretty low grade steel I used since it was so brittle.

    thanks-
    Dustin
     
  4. Isotel

    Isotel

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    rubber bushings at both ends?? No need for a heim with the slip/twist shaft style..

    i dont know man, Let us know what you end up doing, I was planning on installing that type in my truck..
     
  5. cruiser ken

    cruiser ken

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    Convert your fixed end to a shackle and make the whole thing out of the larger tube that you used for the outer part.
     
  6. woody

    woody unhelpful spotter Staff Member Admin

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    if the slip-portion of the bar isn't lube-able, then I can see where it might have bound....

    I personally am not a fan of the slip-type setups, my shackle-type never failed me, 1" .250 wall with a 5/8" heim....

    essentially, your setup is a Y-type, not a V type, and it broke precisely where the Y intersects, which is by far the weak point....my original Y-type lasted 1 day, used the same materials for the V-type, and it lasted for a few years until I swapped suspension designs.
     
  7. dustin

    dustin

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    cool. 10-4 on what youre saying about the Y-type. It was a concern of mine as well, though I hoped the materials were strong enough. I didnt realize how much force really was put to the axle.

    I could scratch this one and do the shackle type. Having the front of the bar fixed to my t-case mount, very close to where my driveline mounts to my tcase was a big reason I went for this design. The angles are very similar between the bar and the driveline. I suppose I could also try another build on this design, but make the V portion longer (way more V, but would inevitably still be a Y-type). Hmmm...

    thanks!
    Dustin
     
  8. bustanutley

    bustanutley

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    humm, I was just building my wrap bar and was going to make it a y-type, good thing I havn't welded it up yet, guess I'll find some longer material and make a V-type.

    Thanks for the post and hopfully I can learn from your designs failure :beer:
     
  9. FoYoChe

    FoYoChe

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    I don't know if this works for you, but Dad put one of the over the spring pack traction bars on his Bronco, it has a pretty healthy 400 ford, and he hasn't had trouble since. Before he put it on, his axle would wrap far enough to break the driveshaft at the pinion, this is with a CV so the driveline ran straight into the pinion.
    the design of the bar keeps it in compression only, it has two rubber bushings, and follows the arc of the spring to keep the ride good. I think he got it from James Duff. It looked cheesy when we put it on, but it works really well. He runs 33 x 12.5's with a spool in the back, and its stood up to burnouts on pavement, and jumping in the dunes.

    http://www.jamesduff.com/eb/susp_parts.html
    first one.
     
  10. Wayneraintree

    Wayneraintree

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    This one works well on my 350'ed 55..

    [​IMG]

    [​IMG]

    Sleeving the neck bolstered the strength well and the small shackle handles the torque like a champion.

    HTH
     
  11. Trollhole

    Trollhole THC Supporting Vendor Moderator

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    I like it! The oi who did mine did it all wrong.

    this is what is left of it after the to short driveshaft from a poorly done SOA. I cannot for the lfe of me understand why there is only one mounting location in the back instead of two.

    [​IMG]

    notice the two hole where the anti wrap bar used to be

    [​IMG]
     
    Last edited: Jun 22, 2005
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