Just bought a 1983 SD with brake problems. I have put on new pads, new fluid, new master cylinder (the old one felt just like the new one - also the booster unit does not look that old). Have bled the brakes. When stepping on brakes with engine off, or master cylinder plugged everything feels good. When stepping on the brakes for the first time in an application, with the engine running, pedal is low. with one pump, the pedal comes up but creeps under steady moderate pressure (it seems to creep less with greater pressure). I lose no fluid, and have no puddles. The stopping performance is not so well as with my 82 240D, but the vacuum readings I take are similar to those on the 240D. Is there something to bleed or adjust besides callipers and master cylinder (a proportioning valve or similar?)