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  1. #1
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    How to tell if a roller or ball bearing is bad

    I'm currently working through a bit of a problem with my c900: the gearbox is making an rpm-dependent whine. It means I may have a bad bearing somewhere, or the new primary gears I've put in are worn.

    This being the case, I've been looking into how to spot a worn bearing, and came across this very good guide, which I thought I'd post here:
    http://www.vibanalysis.co.uk/technic...0as%20follows:
    Be sure to scroll all the way to the bottom and click the links to see some fantastic roller bearing carnage photos and descriptions!

    Do I really have nothing better to do than look at pictures of buggered roller-bearings? Does anybody care?
    Ask me a question about your c900! I promise I either can answer it or know someone who can

  2. #2
    Jose Luis
    Prominent Member jlrSAAB's Avatar
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    Quote Originally Posted by euromobile900 View Post
    I'm currently working through a bit of a problem with my c900: the gearbox is making an rpm-dependent whine. It means I may have a bad bearing somewhere, or the new primary gears I've put in are worn.

    :
    it is an automatic or manual transmission? it should be good to see the description MT or AT in the profile "My saab"
    it could be the flywheel noise.

    - I have some pictures of manual transmission clutch kit fried due sliding, if you are interested about it...


  3. #3
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    It's a manual. I'm very sure it was the bearing. I just took it apart and it was spinning on the aluminum shaft. Wore away the shaft so much that I needed to use Loctite and a punch to make clearances tighter. I hope this has fixed it, but only time will tell.
    Ask me a question about your c900! I promise I either can answer it or know someone who can

  4. #4
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Here's my shot-bearing. It was very shot, in multiple ways. First off, it had a discoloration on one side of the inner race, presumably caused by heat. This was when it was installed originally. I unwittingly put this bad bearing into my own car!
    Name:  IMG_4374.jpg
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    It spun on the aluminum shaft, forcing me to repair it.
    Name:  IMG_4371.jpg
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    Upon disassembling the bearing (removed from upper primary sprocket using a drift), I found this on the outer race:
    Name:  IMG_4392.jpg
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    False Brinelling (straight line shaped marks) and some fretting.

    Rollers show some small wear marks:
    Name:  IMG_4393.jpg
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Size:  35.6 KB

    Inner race shows massive fretting:
    Name:  IMG_4395.jpg
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    Not coincidentally, this is only present on the same side as the "overheat mark":
    Name:  IMG_4396.jpg
Views: 1212
Size:  27.0 KB

    Nasty stuff, eh?
    Last edited by euromobile900; 20 December 2010 at 18:15.
    Ask me a question about your c900! I promise I either can answer it or know someone who can

  5. #5
    Jose Luis
    Prominent Member jlrSAAB's Avatar
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    - I have some pictures of manual transmission clutch kit fried due sliding, if you are interested about it...










  6. #6
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Well, that is quite a burned clutch there. It looks as though some of the metal was reddish-hot from friction! The blueing of the pressure plate and bits of metal embedded in the disc are giveaways! Were you able to reuse the flywheel?
    Ask me a question about your c900! I promise I either can answer it or know someone who can

  7. #7
    Jose Luis
    Prominent Member jlrSAAB's Avatar
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    my dealer replaced all parts:
    -flywheel
    -clutch kit,
    -slave cylinder.


 

 

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