I finally got the brake master cylinder back for my 1989 Porsche 928 S4. It looks better than new ones. The company I used was White Post Restoration out of White Post, VA. This brake master cylinder was sleeved and has a life time warranty. I highly recommend using White Post Restoration. The packaging they used was very professional.
I plan on now removing the power brake booster. During the troubleshooting process the brake booster displayed symptoms of being bad. It also is very rusted. Behind the brake booster area and nearby,, I will be adding more insulation to the firewall to reduce the amount of heat passing through the firewall.