Broken Shimano XT Bottom Bracket Cup...

Discussion in 'Cycling Equipment' started by Wes Crout, Jan 29, 2003.

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  1. Wes Crout

    Wes Crout Guest

    I have just recently purchased some '02 XTR equipment (BB, Crankset & Shifter/Lever Combos) that I
    am wanting to install onto my bike (obviously). My old bottom bracket, a non-splined Shimano XT
    (BB-UN72) seems to want to get in my way of doing so. I removed the non-fixed BB cup from the left
    side, then the rest of the bottom bracket. The problem enters here. The movable BB cup from the left
    side (cheaper plastic) broke in half somehow while still in the frame. I therefore have half of the
    cup remaining. I am unsure how to safely remove this without damaging the threads on the frame. On
    the portion of the cup that removed, there are only about 4 or 5 of the threads, leaving a good
    portion of cup in the frame to work with. I cannot grip it with anything that I know of, so any
    suggestions would be greatly appreciated. I will obviously take it the the LBS sooner or later if I
    am unable to remedy this myself. I would call them right now, but they are closed until the morning.
    I was in a rhythm, and would like to continue this project tonight. Thanx in advance...
     
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  2. A Muzi

    A Muzi Guest

    "Wes Crout" <[email protected]> wrote in message news:[email protected]...
    > I have just recently purchased some '02 XTR equipment (BB, Crankset & Shifter/Lever Combos) that I
    > am wanting to install onto my bike (obviously). My old bottom bracket, a non-splined Shimano XT
    > (BB-UN72) seems to want to get in my way of doing so. I removed the non-fixed BB cup from the left
    > side, then the rest of the bottom bracket. The problem enters here. The movable BB cup from the
    > left side (cheaper plastic) broke in half somehow while still in the frame. I therefore have half
    > of the cup remaining. I am unsure how to safely remove this without damaging the threads on the
    > frame. On the portion of the cup that removed, there are only about 4 or 5 of the threads, leaving
    > a good portion of cup in the frame to work with. I cannot grip it with anything that I know of, so
    > any suggestions would be greatly appreciated. I will obviously take it the the LBS sooner or later
    > if I am unable to remedy this myself. I would call them right now, but they are closed until the
    > morning. I was in a rhythm, and would like to continue this project tonight. Thanx in advance...

    Since the lip is off the cup, did you try just unscrewing it? There's nothing preventing it from
    turning now. Press outward with both thumbs while turning.

    If you tap under the edge of it with a pick or a small chisel ( or someone else's screwdriver!) they
    are easy to shatter. No risk of damaging the frame's threads to any meaningful extent although there
    may be a small ding where the tool hit.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  3. Jeff Wills

    Jeff Wills Guest

    "A Muzi" <[email protected]> wrote in message news:<[email protected]>...
    > "Wes Crout" <[email protected]> wrote in message
    > news:[email protected]...
    > > I have just recently purchased some '02 XTR equipment (BB, Crankset & Shifter/Lever Combos) that
    > > I am wanting to install onto my bike (obviously). My old bottom bracket, a non-splined Shimano
    > > XT (BB-UN72) seems to want to get in my way of doing so. I removed the non-fixed BB cup from the
    > > left side, then the rest of the bottom bracket. The problem enters here. The movable BB cup from
    > > the left side (cheaper plastic) broke in half somehow while still in the frame. I therefore have
    > > half of the cup remaining (snip)
    >
    > Since the lip is off the cup, did you try just unscrewing it? There's nothing preventing it from
    > turning now. Press outward with both thumbs while turning.
    >

    Since the cup fell to pieces, I wonder if there's some corrosion holding the cup in place.

    > If you tap under the edge of it with a pick or a small chisel ( or someone else's screwdriver!)
    > they are easy to shatter. No risk of damaging the frame's threads to any meaningful extent
    > although there may be a small ding where the tool hit.

    Carefully quartering the cup with a hacksaw blade first will probably make this easier, also. I'd
    really clean out the threads and inspect them before inserting the new cup. No sense in getting it
    jammed or cross-threaded in a buggered BB shell.

    Jeff
     
  4. Michael Dart

    Michael Dart Guest

    "Jeff Wills" <[email protected]> wrote in message
    news:[email protected]...

    > ....I'd really clean out the threads and inspect them before inserting the new cup. No sense in
    > getting it jammed or cross-threaded in a buggered BB shell.
    >

    That is important advice for anyone installing a new BB even if the old one came out nice and easy.
    Make sure those shell threads are clean, "like it's your job!". I learned my lesson the hard way.
    One piece of grit is all it takes to bugger up those soft plastic/aluminium threads.

    Mike
     
  5. Dax

    Dax Guest

    On Thu, 30 Jan 2003 06:58:25 -0500, "Michael Dart" <[email protected]> wrote:

    >
    >"Jeff Wills" <[email protected]> wrote in message
    >news:[email protected]...
    >
    >> ....I'd really clean out the threads and inspect them before inserting the new cup. No sense in
    >> getting it jammed or cross-threaded in a buggered BB shell.
    >>
    >
    >That is important advice for anyone installing a new BB even if the old one came out nice and easy.
    >Make sure those shell threads are clean, "like it's your job!". I learned my lesson the hard way.
    >One piece of grit is all it takes to bugger up those soft plastic/aluminium threads.
    >
    >Mike
    >
    >

    to remove the remains - get a big file, just a bit smaller than the bb... they are generally
    tapered. Feed the file in till it snugs up against the plastic. The file's sharp edges will grip
    well enuff to thread it out. You want a file with a taper h that will touch the plastic without
    touching the threads - Ъ×
     
  6. Wes Crout

    Wes Crout Guest

    I would like to thank you all for your advice. The old cup remains have successfully been removed,
    and I will be installing the new BB and crank tonight. I will clean all threads immensely, like it
    is "my job." Thanx again.

    Wes
     
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