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Demo 8 carbon bottom bracket stuck

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Demo 8 carbon bottom bracket stuck
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flag rbod957
Posted: Nov 18, 2023 at 17:15 Quote
I got a 2016 s works demo 8

It’s my first time with a carbon frame bike, I noticed there was some play in the main pivot bearing so went to change it.

When I try to turn the spline on the bottom bracket or concentric bearing using the tool
That’s part of the bike, it is seized super tight. Tight enough that I snapped a 1/4 punch pulling on it.

Do you guys have any suggestions for unthreading this out of the linkage? I have access to a welder and all mechanical tools but being a carbon frame I’m hesitant to do anything with heat.

Thanks
flag BenLow2019
Posted: Nov 19, 2023 at 13:37 Quote
I’m trying to understand what you’re doing. Are you trying to remove a threaded bottom bracket? If so then are you turning it the right way? One side is reverse threaded. If you attempt to unscrew the reversed side by turning it counter clockwise then you’ll end up tightening it.
flag aegiz
Posted: Nov 19, 2023 at 15:39 Quote
Haven't personally worked on this bike, but maybe you'll find some useful info here

https://www.pinkbike.com/forum/listcomments/?threadid=194557&pagenum=53
flag zeeino
Posted: Nov 21, 2023 at 17:13 Quote
No experience with seized BB in a carbon frame, but I've dealt with seized seat posts. Penetrating fluid is likely your best bet.. And maybe some prayers if you're into that.

If the penetrating fluid doesn't help, the next option is risky. Someone handy with a saw can surgically cut off enough material to loosen things up.

Good luck!
flag rbod957
Posted: Nov 21, 2023 at 18:29 Quote
The demo has a weird through bottom bracket that threads into the opposite side of the pivot arm. Luckily I got it off without breaking it and without wrecking the threads but specialized’s method didn’t work. I needed to use a 3 foot long pipe wrench and somehow nothing cracked or snapped.

All the bearings inside the pivot were grenaded and definitely had a little water in there. My next option was gonna be cutting it with a dremel to weaken it but glad we didn’t have to find out how that option went
flag rbod957
Posted: Nov 21, 2023 at 18:31 Quote
aegiz wrote:
Haven't personally worked on this bike, but maybe you'll find some useful info here

https://www.pinkbike.com/forum/listcomments/?threadid=194557&pagenum=53

I had used this thread and breakdown for info but it was substantially more difficult to get mine off. Eventually it went though
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