Have been reading this thread with interest. A friend of mine had the problem of a soft pedal. We bled brakes, changed calipers, check MC & Brake booster. We then got down to checking every line on the car and found a extremely small leak in a brake line. This thing would not leave a puddle of fluid or give any highly visible indication of a problem. It took us about 2 hours of looking at everyline and feeling every line until we found this very small leak. we replace that section of brake line and the problem went away. I mean this was a strange problem.

Drive well.