Dave W wrote:" In late 1997/early 1998 they phased in a new, much improved bottom bracket shell. The original shell wasn't bad, but because the internal aluminum sleeve ended flush with the carbon fiber surrounding it, it was possible to put a compressive load on the carbon when installing a bottom bracket, which, in some cases, caused a disbond between the aluminum shell and the surrounding carbon. This didn't happen often, but we did see some frames that had to go back for replacement (under warranty) of the bottom bracket shell.
The frame in question is circa 2007 but the BB construction is similar to as you describe above in that the internal aluminium sleeve is close to being the same width as the CF surrounding (albeit the sleeve did seem to protrude maybe 1mm beyond the CF surrounding). The ease with which I removed the sleeve certainly suggests a disbonding.
I visited my local Trek dealer today - over the phone they were optimistic of a fix having resolved similar problems (BB sleeves coming loose) in the past, but on seeing the frame they do not feel that there is enough surface area inside the BB surrounding to adequately secure (a locally made) new sleeve. Further, they were of the view that this problem had been developing for some while - given that I've only had the bike for about 6 weeks, one wonders if the seller knew of this problem? And in correspondence with others, it does seem that using a ST (square taper) BB puts the most stress on the BB sleeve bonding (as Brucey said up thread).
I am coming around to the fact that this frame is beyond repair, at least in a meaningful way!
One option I'm considering is to manufacture something that would in essence be a one-shot job, e.g. permanently bond some H-II bearings in a sleeve and bond the sleeve into place with as much bonding material as I can get into the space available. Obviously once the BB bearings are worn, then that's the end of the frame.
What 'industrial strength' adhesives are to be had I wonder?