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  1. #1
    Project B
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    Stuck Thomson post in 4130 chromoly frame - ammonia ok?

    I've tried every trick per http://www.sheldonbrown.com/stuck-seatposts.html except for corking up the post and pouring ammonia down through the bottom bracket shell. Will ammonia affect the black anodization or otherwise weaken the seatpost?

  2. #2
    GO BIG RED norwood's Avatar
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    Quote Originally Posted by Roam View Post
    I've tried every trick per http://www.sheldonbrown.com/stuck-seatposts.html except for corking up the post and pouring ammonia down through the bottom bracket shell. Will ammonia affect the black anodization or otherwise weaken the seatpost?

    If your post is truely stuck then it's pretty much toast anyway. That's the whole idea of the ammonia trick anyhow, it eats away a bit of the aluminum surface to release the post. I can't speak from experience as I've never had a stuck post. I've always been a little skeptical of the process but I guess it works.
    1996 Bianchi Veloce
    1993 Bridgestone MB-3
    1992 Trek 700
    1992 Trek 820

  3. #3
    Junior Member
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    Have you tried chucking the seat post into a sturdy bench-mounted vise, and turning the frame? That gives you tremendous leverage and will usually allow you to turn the post in the tube, which will help distribute penetrating oil and eventually release the post. You can wrap the post in electrical tape or other padding, and if you're careful, the post will be undamaged.

  4. #4
    Surf Bum
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    This stuff may be worth a try. It's brilliant:


  5. #5
    Project B
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    Quote Originally Posted by gw360 View Post
    Have you tried chucking the seat post into a sturdy bench-mounted vise, and turning the frame? That gives you tremendous leverage and will usually allow you to turn the post in the tube, which will help distribute penetrating oil and eventually release the post. You can wrap the post in electrical tape or other padding, and if you're careful, the post will be undamaged.
    According to Mr. Brown, penetrating oil is almost useless on aluminum oxide - the likely culprit, as the bike saw a lot of salt this winter.

    I emailed Thomson and received confirmation (within two minutes!) that ammonia is ok to use. Fantastic customer service!

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