The calipers were rebuilt with no issues, but after the system was bled, the left master cylinder would not spring back after being pushed. Hmm. Strange. Rebuild kits were ordered and with parts cleaned and ready to go back together, it turned out the main piston plunger shaft is bent. My best guess is a panic stop by the former owner. My second guess is that the other side may be bent and could result in a locked brake on landing. So before I order a replacement cylinder, I think the other one needs to come out and be checked.