Posted: Fri Jun 01, 2007 3:13 pm
The Volvo caliper I was suggesting is the same one func412 is using, a direct bolt-on to the 412 spindle, no modifications. The credit must go to him. It is the 4 piston caliper found on many 200 series Volvos circa 1980's. There were TONS of these cars in the local pull-a-part yard. I have some nice rebuilt ones I got for $150 on ebay, but for fitting purposes I pulled a used pair myself for $18. Func412 was looking at rotors with a diameter between 296-302mm. I don't know the thickness of the clamped part of the rotor new, it doesn't give the specs in the Brembo catalog. The min. thickness is listed as 22mm, so my best guess is that they are probably 24mm new. Maybe I should make some friends with some guys at a Porsche dealer service center, and they could slip me some rotors worn past spec out the back door for me... 
Right now, the calipers I have, as they were removed from the car, have 22mm between the pads, which look like they have substantial life left in them. I don't know if they can safely open and function wider, I haven't tried it yet. BillK, thanks for filling me in on the Porsche disc center hole sizing issue, I haven't held the appropriate Porsche disc in my hand and was thinking it might be the same as the wheel center bore, which apparently it isn't. As you suggested, this would be beneficial, as rotors could be replaced without modification. Ray, I will heed the warnings about the centering ring. If going the route of buying those welded/studded rotors, I would base the decision on whether one could request the centering ring to be left on.
Right now, the calipers I have, as they were removed from the car, have 22mm between the pads, which look like they have substantial life left in them. I don't know if they can safely open and function wider, I haven't tried it yet. BillK, thanks for filling me in on the Porsche disc center hole sizing issue, I haven't held the appropriate Porsche disc in my hand and was thinking it might be the same as the wheel center bore, which apparently it isn't. As you suggested, this would be beneficial, as rotors could be replaced without modification. Ray, I will heed the warnings about the centering ring. If going the route of buying those welded/studded rotors, I would base the decision on whether one could request the centering ring to be left on.