Broken swaybar sleeve bolts

Chassis, Suspension and wheels

  1. SixBanger

    SixBanger Well-Known Member

    Messages:
    264
    Likes Received:
    29
    Joined:
    Jul 31, 2018
    Location:
    The Netherlands
    Hi,

    After driving for a while with the new polyurethane sway-bar bushings the steering performance is better than before.
    But there is an problem with that after a speedbump one of the sleeve connection bolt just has broken off.
    The bolts are 307A, grade 1, quality. So it is not the strongest bolt.

    I get some grade 5 5/17 bolts. But am thinking why the bolts just broken after a while driving over speed bumps?

    Can that be that the connection in the retainer link (to K-body) give to much friction? These are also new and have fit them with some silicone grease.
    Or there is something wrong with the retainer link units.

    Thanks!

    Knipsel.PNG
     
  2. Opticon77

    Opticon77 Well-Known Member

    Messages:
    238
    Likes Received:
    113
    Joined:
    Apr 15, 2018
    Location:
    SE PA
    Those stock swaybars don't have end links to accommodate extreme control arm articulation (like over a speedbump) so the twist puts direct and uneven tensile pressure on the end bushings and bolts. If you upgraded the bushings that means more tensile pressure went into the bolt head.

    Upgraded bolts should do the trick. Grade 5 will have double the tensile strength of your current 307a.
     
  3. SixBanger

    SixBanger Well-Known Member

    Messages:
    264
    Likes Received:
    29
    Joined:
    Jul 31, 2018
    Location:
    The Netherlands
    Okay good to see that mounting grade 5 bolts should fix the problem. Why didn't they sell in the first place 5 grade bolts? I mean, I am not the only one where the bolt has been broken?
     
  4. Opticon77

    Opticon77 Well-Known Member

    Messages:
    238
    Likes Received:
    113
    Joined:
    Apr 15, 2018
    Location:
    SE PA
    Factory bolts with the rubber bushings would never have seen that kind of load because the rubber end bushings soak up the slight changes in angle as the control arms reach its extents.

    Or were the bolts new with the polyurethane kit? If so what brand?
     
  5. Opticon77

    Opticon77 Well-Known Member

    Messages:
    238
    Likes Received:
    113
    Joined:
    Apr 15, 2018
    Location:
    SE PA
    Look at how much angle that eyelet on the end of the bar has in between the two endlink washers (right side of photo)...

    frontend4.jpg

    If you push that control arm any higher (lower the car and/or hit a bump) that eyelet is going to be spreading/prying at the washers. Stiffer bushings would only help it pop the head of that bolt off like a bottle cap. This is why aftermarket sway bar kits add a proper end link.
     
  6. SixBanger

    SixBanger Well-Known Member

    Messages:
    264
    Likes Received:
    29
    Joined:
    Jul 31, 2018
    Location:
    The Netherlands
    Thanks Opticon77.

    I had to say that I first replaced the worn rubber with an poly set of ENERGY SUSPENSION. Bolts were also supplied with this kit (I have checked, grade 5).
    But after a few months, one apparently broke. In the first instance I assumed that it had been come lose.

    Then I have replaced for the left side with an Moog set (307A bolt).

    Now I can image that the stiffer poly bushings can stress the bolts more.
    But with the fresh poly bushings I did have some 'issues' to install the new bolt. First I did install the retainer links to the K-frame and Then the the sleeves. Doing this way I only get sleeve on one side install easy, the other side (right) give some problem. I had to push the sway bar up to the torsion bar to install the other bolt (2 inch ish).

    I did check and measure the different mounting places. It seems like that were no big difference.



    But the strange the next thing did result in a better installation.

    Now I did install and torque down the sleeves before I mount and torque the retainer links. The strange thing was that it was now installed without any difficulty. And probably there should now less tension on the bolts. But we'll just see it.