Mercedes like most cars today utilizes a dual circuit master cylinder, in the case of 124 cars the circuits are front and rear. Maybe the brake pressure being applied by the divided circuits is not proportioned correctly for some reason?

Disappearing rear brake pad could be attributable to, too much rear circuit pressure being applied or too little front circuit pressure being applied. Either of those would lead to the greater loss of pad material in the rear.


With a deficiency at the front brakes the rear brakes would have to be working and wearing harder to stop the car so that could be a contributing factor as well.