I have been vibration free for about 4 months. I am totally convinced the Volvo service manager was correct. I thought just doing the pads in the rear would work but he thinks that somehow the rotor, even though nearly new, gets to a state, perphaps due to heating, that the pads "skid" a little on it rather than bite. I have a 240 and a 850 and have been doing my own brakes for about 3 years. I don't consider myself an expert but I have learned a lot. I was buying PBR or Mintex pads and Brembo rotors to save a few dollars. But at least for the 850 I will stick with buying Volvo parts. Another point to consider: the book says to change the caliper bolts each time you change the rotor. However only Volvo rotors come with the caliper bolts. They are hard to find otherwise. So I now have new bolts once I installed the Volvo rotors.