Suspension Brakes Need Advice! Stripped lower shock mount!

Discussion in 'Tuning and Performance' started by NAProf, Jan 9, 2010.

  1. NAProf

    NAProf New Member

    Jun 1, 2009
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    Well I got in a hurry and screwed up again. My son and I were installing Koni FSD's on my R56 and everything was going great. I showed him how on the left and he was doing the right (he never wanted to work on cars before and now that he is an adult he decided to learn). Things went well on the front and I wasn't paying much attention to his efforts on the rear. Unfortunately he torqued the upper bolts before inserting the lower bolt and must not have had it aligned well. He wasn't going to make me think he was a wimp so he muscled the bolt in, only to strip the threads in the aluminum trailing arm.
    So what to do now. The trailing arm is $350 and it appears to be a b***ch to replace. I'm think I can drill out the hole in trailing arm to clean it up a bit and then grind a flat spot on the outside of the hole for a bolt and washer. I have access to lots of quality high strength bolts and if necessary can make one in the machine shop at work.
    So do you guys think bolting the lower shock mount is a feasible solution?

    Not so cheery,
    Greg
     
  2. miniconcarne

    miniconcarne New Member

    May 5, 2009
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    Do you have room to get at it with drill?

    If it was me, I would look into using a Keensert (better than a Helicoil).
    Stronger than the aluminum and easy to install.

    See if the machine shop has some or can get some. You will need room to drill and tap the control arm to accept the insert.

    Example:
    Keenserts - Keensert Key-Locking Inserts, Keysert Keylocking Inserts, Miniature Key-Locking Inserts, Thinwall Lightweight Key-Locking Inserts, Extra Heavy Duty Key-Locking Inserts, Lokserts, Tridair, Alcoa, Fairchild Fasteners, Maryland Metrics
     
  3. Motoring Magic

    Motoring Magic New Member
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    Dec 13, 2009
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    ditto


    what he said exactly! even if you had to take the arm off, that would be the way to do it, not replace it
     
  4. Way Motor Works

    Way Motor Works New Member

    May 4, 2009
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    I've seen this a couple times before. That's why I always start those bolts by hand.

    I'd put in a keensert, or take the arm off and have a machine shop fix it. those arms are expensive.
     
  5. maacodale

    maacodale Club Coordinator

    May 7, 2009
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  6. NAProf

    NAProf New Member

    Jun 1, 2009
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    Hey thanks for all the feed back. Seems this site is much better for technical quesions than that other site :Thumbsup:. Based on miniconcarne's suggestion I looked into keenserts and agree it is likely the way to go. So I am off to the garage to take the trailing arm off so I can take it to work tomorrow and talk to the machine shop guys about how to make this happen (I am an engineer, but rely heavily on these guys telling me how things really are).
    Cheerier than last night,
    Greg
     
  7. Minidave

    Minidave Well-Known Member
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    Dec 22, 2009
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    A good learning experience for your boy, have him remove the arm so he can learn about what he did....

    I agree with the insert, even tho this is a critical place, the insert will make the threads stronger if done right. Letting the machine shop guys do it is a smart way to go, they work with this stuff all day so their expertise means it has a good chance of being done right. On re-assebly, patience and hand start all fasteners is the lesson for your son, if it doesn't feel right, pull it out, look carefully, and try again till it does - one that will serve him all his life
     
  8. jeff@txwerks

    [email protected] New Member

    May 4, 2009
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    You may also be able to find a TimeCert the correct size. We used these on a stripped out spark plug and they are way better than helicoil. We bought them at hrpworld.com - they come with the tap tool and you specify the timecert size.

    Regards,

    [email protected]
     
  9. NAProf

    NAProf New Member

    Jun 1, 2009
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    Got it fixed - Thanks for the help.

    A big thanks for all of the timely advice on fixing my problem. I ended up pulling the trailing arm and taking it to work, The machinst there said they would use a Helicoil because the trailing arm is aluminum and the bolt would hold fine in that (and they thought they had the size I needed). Turns out I had to order the M14x1.5 size from McMaster-Carr, but got it next day. So the boys drilled it out to 9/16th, tapped it with the supplied tap, and then used blue lock-tite for a little added assurance when they threaded in the insert. Worked great. And while I was waiting for that to happen I called Way (Way Motor Works) and he sent me a set of H-Sport bushings to replace the ones Alta supplied on my 19mm rear sway bar. They give smoother operation and have a fitting for periodic greasing.
    So in the end it all worked out and both my son and I have learned some lessons. He knows to thread bolts with his fingers to begin and I know to give better instructions when I am getting rookie help.

    Cheers,
    Greg
     

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