I am replacing the rear brake on a vintage bike, a 1986 ROSS. I removed the Shimano 600 brake that was on the bike, and I am trying to install a Shimano Sante. The pads will not reach the wheel rim (700c)when adjusted to the lowest setting!!! I looked at the Shimano 600 rear brake that I removed, and the arms appear to be the same length, actually there is little difference between them. The bolt, however, looks to have been bent just a little. I'm completely surprised and frustrated that I may not be able to use the Sante brake. Did I lose a part or something? The front brake exchange has presented no problem.