Originally Posted by
Drillium Dude
I'm sure someone will come up with a pic that proves me wrong, but every time I've seen a joint fail it's been the tube that cracks/breaks, not the lug or BB shell. It makes sense, as the tubing is much thinner than the shell or lug.
You called it
This is from
my thread about my commuter Holdsworth/Claud Butler. The bronze braze filler didn't penetrate all the way through under the lug, so the lug cracked due to fatigue. While economics/pricing suggest that a Guerch' shouldn't suffer from this sort of bad workmanship, you never know.
In addition, if it is a crack in the lug due to bad brazing, the tubes beneath should not be cracked. This means that you wouldn't be able to tell by looking inside the bottom bracket.
If you are going to strip and repaint it anyway, why not file/chip away the paint there to investigate?