I had the same issue on my Z31. Try taking the calipers off and greasing up the slider pins. They were all rusty and nasty on that car. Some wd40 helped to clean them up and after I got it all back together with new grease, they slid easier than the other calipers that didn't give me any issues to begin with. I ended up cleaning them too; it's a very cheap and easy fix.
:the other calipers. I'll keep checking the wear on that cylinder just to make sure because I'm not sure what caused it to wear so uneven like that.