BB lock rings

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Brucey
Posts: 39328
Joined: 4 Jan 2012, 6:25pm

Re: BB lock rings

Postby Brucey » 29 Jun 2020, 2:09pm

Trigger wrote: Can't shift either cup, tried a punch in one of the holes but it is just boring its way through the ally.

I wondered about making some flats on the cups and trying a big spanner?


look at the pictures of the assembly; there are no 'cups' there is a centre tube which is stuck in the frame, which was originally a sliding fit in the BB shell, not reliant on threads (which is the whole point of the thing).

Since the BB unit is scrap now anyway (and BTW shimano cranks fit OK on Mavic tapers IIRC...? and even if they don't fit perfectly they are not the only cranks.....) then using destructive means to remove the BB unit is now your only choice. I expect heat and a big hammer to be involved. Then you will need to repair the frame, probably.

BTW the bearing adjuster may well be seized up but it is meant to be turned using the appropriate mavic tool, not just battered with a hammer and punch. Even if it were not seized that would definitely wreck it.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Pneumant
Posts: 166
Joined: 7 Oct 2010, 8:25pm

Re: BB lock rings

Postby Pneumant » 29 Jun 2020, 4:25pm

+1 ^^
As already mentioned this unit does not use cups! This unit is a snug fit in the BB shell, support the frame and knock it out. These BB's were expensive back in the day, all alloy construction and hollow precision axle. Think better than Record / Dura Ace / Superbe Pro quality. As previously mentioned these units are rebuildable. They have value as compatible with 90's Campag. Basically you can use one of these BB's instead of a 111mm hard to find Campag BB or on one of the lovely (but heavy) Mavic star chainsets 8).

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Trigger
Posts: 1441
Joined: 6 Aug 2010, 11:54am
Location: Derby/Notts

Re: BB lock rings

Postby Trigger » 29 Jun 2020, 4:32pm

Well nobody will be using this one :lol:

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Trigger
Posts: 1441
Joined: 6 Aug 2010, 11:54am
Location: Derby/Notts

Re: BB lock rings

Postby Trigger » 30 Jun 2020, 6:48pm

Galvonic corrosion has well and truly got a hold here, the two pieces are now one, which is pretty much what I suspected after the last line of attack failed.

Unfortunately I deal with it almost on a daily basis at work and it's no less of a pain in the backside there, in fact more so there due to the location.

So I think the only course of action left is the stuck seatpost dissolving trick.