It's probably a seal in the MC. If your fluid level is fine, and you don't have any leaks, it can only be that if it's a spongy pedal. I had one go, and you could get one good throw out of the pedal, and then anything after that you could walk the pedal all the way to the floor. Clearly pressure isn't holding if you have a soft pedal. The coming and going of the pedal firmness again points to a seal in the MC. Replacing the unit is probably what you are looking at. Better take the old one with you to the parts store to make sure they get you the correct replacement also. I'm not real trusting of the counter man's computer with all the drum/disc/power/maunal combos' that were out there.