After a few new gray and bald spots, I've just repaired the brakes on my wife's 92 940. First symptoms were low pedal and vibration when applying brakes. I purchased new pads and installed them and "suprise" no pedal at all. I pressure bled the system, although I couldn't concieve how any air had entered, and still I couldn't get a hard pedal that would repeat. I could pump them up, but after releasing them for a few seconds, back to the floor it went. Master cylinder? I've seen it before on my 240's. I replaced the master cylinder, bled the system again, and I still had the same problem. I jacked the car up and removed all 4 wheels and proceeded to pinch off the brake lines. With both front wheels closed off, I had a hard and high pedal so I knew that the problem wasn't in the rear. With the rear still closed, I re-bled the front brakes again and still had no luck. I was leaning against the car with the door open pumping the pedal, scratching my head, looking at the left front caliper when I saw a strange thing occuring. The caliper piston was deflecting the rotor everytime I pressed the pedal. At the same time, the opposite side brake pad wasn't even touching the rotor. The caliper slide pins were frozen and the caliper couldn't move. Both front wheels were the same. I removed the caliper mounting, and while holding the bracket in a vise, I beat the pins out with a brass drift, cleaned and greased them and re-installed the whole shebang. "Lo and behold" a full and hard pedal, the best brakes since I bought this car used. I was getting full piston travel all of the time, The caliper just wasn't squeezing the pads together against the rotor, merely deflecting the rotor, hence the vibration. I'm a old 240 man, and I've never seen this before. These pins will be a regular maintenence item for me from now on. I hope that this helps someone, sorry for the long post.