M calipers, How you differentiate?
 

Hi to all,

I have about 3 sets of calipers. I cleaned and painted them about 10 years ago. Now, How can I tell:
1. If they are front or back?
2. If they are for solid rotors or vented?
I believe that they were 1966 and 1969 possible 912, I am all confused :confused:

Thanks and greetings from Georgia,

Jose

The fronts will have the larger pistons. If you post some pictures some here will be able to tell if they are for solid or vented rotors.

Vented M calipers will always have a pair of spacers between the two caliper halves.
Front M calipers will generally have the fluid inlet straight out the back in line with the pistons. 911 pistons are 48mm, 914 pistons are 42mm.
Rear calipers will have the fluid inlet pointing down, so at a right angle to the axis of the pistons. 911 pistons are 38mm.
If you have SWB (1968 & earlier) the mount ears on the rears are smaller and closer together and have a crossing line; these are L calipers.