Originally Posted by
rccardr
If you disassembled the caliper down to the central bolt, you likely backed it out of the nut on the front more thanit was originally. Thus, more exposed bolt on the back side.
Not able to do this with this design. This caliper has the "traditional" center bolt and spring holder style where the spring carrier is "one" with the center bolt. On one side of the spring holder the arms are adjusted for free movement via the two nuts on the outward end (much like Campy NR and millions of other calipers). The amount of center bolt on both ends, beyond the spring carrier, are fixed and not changeable.
More recent Shimano calipers are of a different design with the center bolt's outward end a fixed item and the spring carrier and a knurled lock nut are the adjusting elements. IMO a more hassle prone design but not rocket stuff either.
One other possibility is that the recessed nut for the back got somehow swapped with that of the front. These nuts are available in varying lengths too. But my first thought of the missing toothed spacer is the route I would first check into as it gets you two bennies. One in that the brake fits the frame properly and the other is that the caliper is now better held from rotating off center. Andy