Denny,
my personal experience with the problem was with a 75 camaro that I had from new. I had the MC/booster replaced at a dealership and the brakes overheated on the way home, about 1 mile! When I got out, I could smell the glue. I took it back and they adjusted the linkage for the MC.
If the car has a MC for a disc/drum setup, there may be no residual valve for the front system. That may take a separate valve. You are sort of in no man's land with a partially updated brake system.
