I rebuilt some Shimano 8 speed STI shifters. There is a special nut that needs to be removed with a special tool. I made the tool myself out of a socket and dremel tool. I took photos with my phone every step of the way because there are so many little parts that are in a very particular order. It was a pain and if not for the photos I would not have been able to put them back together. When I got them apart, the problem was old grease that had taken on the consistency of old peanut butter so that nothing could move. I realized then that I did not need to take them completely apart and only needed to take them apart to a certain point and then soak the parts in solvent.