I took apart my 911 M calipers tonight and noticed that the pistons are different on the passanger side than the drivers side?

I have no idea if they came from the same car or not, I do know that the piston diameters are the same and other than the pistons (and guide pins), they appear to be identical.

thanks

anyone??

Mike: Is the guide pin (I am assumeing like the 914 has in the front) broken off? I have a front stcok 914 caliper in which someone used different pistons (hollow on outside) and hence they snapped off the cast in guide pins to make it work. I am replacing that bastard caliper, interesting what folks do.

A lot of the VW calipers have the 'hollow' pistons, but I haven't seen it with the 911 calipers. I'd have to think that the caliper came from a different vehicle. Perhaps it could be a very early 911 caliper, I really don't know for sure.

Later M-Calipers seem to come with the cup type pistons. My guess is over the years someone replaced the caliper because it was stuck and the shop simply ordered a replacement w/o specifying.