brakes calipers piston

I just currently overhauled the rear brake calipers and have lost the rear brakes I have tested them on dirt and only the front locked up I then jacked it up and the brakes were applied the rear did not break I have been told that the 75 has a diifferential valve so that when the car is off the...

Recently got back to my Sud project and wanted to put 33QV vented discs and brake calipers (ATE) I got with the 1.7 engine. After disassembling the calipers I found that one piston was damaged (as you can see in the pics). So the questions are: -Is it possible to get such a piston from another...