I appreciate the the input from everyone. I have not replaced the brake lines or flex lines. My best guess is that something is "check valving" as 3B says or trapping hydraulic pressure in the line. I'll plan on replacing the old flex lines in case this is the cause. It was on my list of things to do anyway. The other possible cause is the master cylinder. Any advice on adjusting? My shop manual is a little vague on this. Thanks. Joe