How pitted for a caliper to be replaced?

[sfoster13]

I'll post pics this evening, but when I started my caliper rebuild this weekend, I found that one of the pistons was fairly pitted. Just the top ring, no other area. The pitting on the top ring was pretty substantial though. How much pitting is okay before you have to replace it?

Thanks,
Sean

[Early_S_Man]

Sean,

Take a look at the pics in these threads ... if the discoloration cleans up as well as the pics in the second thread, then you can trust the piston after a rebuild, otherwise, get replacement pistons or calipers! I always use Ultrafine Scotchbrite -- the burgandy or purple kind -- to clean rusted or discolored caliper pistons, along with a watery-paste mixture with Zud or Bar Keeper's Friend ... house hold cleaner.

Can I reuse these caliper pistons?

M caliper question

[sfoster13]

Thanks, that was very helpful. I think my pistons are okay.

Sean