Most cartridge unit BBs are not meant to be taken apart or the bearings not meant to be accessible for servicing. Their replacement cost is so little that this is the path the industry has adopted when things get worn out. Before I would remove the unit I would get a sense of the range of chainring/crank position options. Can the rings fit closer to the frame and still have the der adjust in or opposite? Will the crank arm ends clear the stays? How's the current chain line front to rear? Then with an idea as to where the crank/rings can end up and still all be good I would look at the replacement choices and decide on the new BB accordingly. Pretty much all (but PHIL and Campy) Bbs will be JIS in their tapers, meaning to fit Shimano and their clones cranks. English threading is also pretty much the standard (but still needs confirming) and the shell width is a simple measurement any one should be able to do. Andy.