I am installing the rear 7900 brake calipers on my 2006 Lemond Tete de Course and I think the rear pivot bolt used to install the caliper onto the frame is too short. The front caliper went in perfectly but the rear one is not. According to Shimano's website, the rear caliper's bolt is 1.5" but there is no way that is going to be long enough. It is #4 in the attached diagram link.
Am I doing something wrong? Are there different lengths available and I need to order a longer pivot bolt?