jeffsr, I disagree with your characterization of my conclusion as a "quantum leap" since that implies unsubstantiated guesswork instead of analysis.
My line of reasoning as to the most probable factors goes like this:
(a) the brake pads are dragging on the rotor, or
(b) the hub is moving and dragging the rotor on the pads.
(a) the calipers are not retracting fully, or
(b) the wheel bearings are degraded or out of adjustment.
(a) the calipers need rebuilding or replacing, or
(b) the wheel bearings need tightening or replacement.
Research resources included:
(a) CD-ROM and paper service manuals for the 124
(b) internet i.e. http://autos.yahoo.com/repair/tree/0.5.html
(c) my brother, import mechanic and foreign car dealer
(d) Mercedes mailing lists and archives
Now, since I have never done this, I could have missed something, so any input will be greatly appreicated.
93 400e, 92k