Join Date: Nov 2000
Location: New Orleans, LA
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I am nut sure about Ultegra, but I'll tell you about my two different sets of different vintage 105 brakes. One set, that are, I believe, 8-speed, has the screw I think Geronimo is describing. A small philips head screw out at the corner on the opposite side from where the brake cable attaches. That is the fine centering adjustment. The other set on a 12 speed from the late 80s has kind of a conical 12 mm hex (outide hex, not Allen head). This is the head of the mounting bolt, but is only an incidental part of the mounting system. According to older repair manuals you use it to adjust the centering by putting a wrench on it and turning the whole mechanism by rotating the bolt. Easy does it, you only need to move it a little. With this setup you don't need to loosen the mounting bolt. I'm not sure if I am doing a good job of describing it. Let me know if you think you have this type of setup and need more guidance. This type can be confusing because the single mounting bolt, a nut and a treaded sleeve type of mounting nut are actually fulfilling three different functions - appropriate tension controlling the brake arm pivot, centering, and mounting the brake mechanism. Each function needs proper adjustment for the brakes to work well.
Mike and others, have I described this more or less correctly? I only recently began to understand how this type of brake mechanism goes together and works, and I'm still not sure I fully understand.
If it ain't broke, mess with it anyway!