Infrequently, the pedal goes further to the floor then normal. The car stops OK, just feels weird as the position changes. Pumping once causes return to normal height. Usually occurs after highway driving without any brake action, then when you step on them, the problem occurs. When things cool down after parking, all is normal again for several weeks, then it repeats. Car is a 940SE Wagon. Vacuum booster? or is the MC bypassing? If bypassing you would think that the pedal would sink to the floor with the engine off, and pressure applied. It does not.
Got me stumped. Already been thru the FAQ, and checked what was recommended there.