I keep killing u-joints...

Discussion in 'Technical' started by facelessnumber, Oct 19, 2012.

  1. facelessnumber

    facelessnumber Drew Pittman

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    Ever since the 351w swap, my car's been hell on u-joints. I keep busting the bearing caps. Stock rearend, C4, stock driveshaft, engine mounts are the same as I had on my 302. It's smooth as can be, there are no driveline vibrations... I am using 1" lowering blocks but they've been on the car for years. I don't think there's anything wrong with the pinion angle.

    I drive the car all the time, and yes I have a lead foot. Is this just part of the deal when you put a lot of torque to a stock driveline, or is something likely to be wrong? I'll just keep putting u-joints in every few months if I have to, but that doesn't seem right. I don't want to ignore a problem if I have one, but I also don't want to be chasing down some non-existent issue either.
     
  2. mercgt73

    mercgt73 Well-Known Member Supporting Member

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    Are you breaking the diff yoke end or the trans yoke end?
    Could wheel hop be snapping your u-joints?
    When you installed the last new ones, were they free to rotate and not binding?
     
  3. facelessnumber

    facelessnumber Drew Pittman

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    It's been the rear u-joint so far. I'm hearing that telltale clank again and I haven't checked, but I'm pretty sure it's the rear one going out on me again. When I installed it last, it was moving smoothly and I greased it up good.

    I'm not having any wheel hop.
     
  4. Mavaholic

    Mavaholic Growing older but not up!

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    Pull the driveshaft and have it checked for trueness and balance.
     
  5. mercgt73

    mercgt73 Well-Known Member Supporting Member

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  6. Joe Dirt

    Joe Dirt six poppin'

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    Overtightning the straps distorts the bearing caps and causes this type failure
     
  7. simple man

    simple man Member

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    Are they ones with the large needle bearings or the small needle bearings? The ones with large needle bearings are garbage! Try to get some that have the small needles and you should be good to go! :)
     
  8. junrai

    junrai Member

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    when you put in your u jioints are you making sure theyre in between the little tabs? Ive done that a few times changing mine. in a rush or cant see or just plain dont to be fixing on anything and not paying attention that will give you trouble. but maybe your rear end has just a little play in it where it slams the ujoint every time you step on the car a little
     
  9. injectedmav

    injectedmav Member

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    I had the same issue and I thought it was pinion angle so I went to hell and back trying to get it just right. I finally got frustrated enough to take the driveshaft to a local driveshaft repair shop. He spun it up on the machine and it was shaped more like a banana than a precision driveline component. He was able to straighten it and rebalance it. So far so good. I had this driveshaft shortened by a different facility and I had returned there when I had the first rear joint failure and they told me it was fine.:hmmm:

    The cap u-bolt torque and using the correct rear joint is critical. The u-bolt caps are thicker and some parts databases show both joints to be the same. I assure you, they are different, just in case you didn't already know.
     
  10. cyclonewill

    cyclonewill Member

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    Took me a few times to figgure that one out.
     

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