Vintage MCE stuff can be made to stop just fine. The problem is that most guys don't know how to properly set up the regulator( Black Box) or don't have access to a scope. If you ever read MCE's setup procedures it will state [ For professional results an oscilloscope must be used]. But having worked for a few companies that were too cheap to get one, I understand the dilemma faced by guys in the field. You do the best you can with what you have. If ES (electric stop) is set too far clockwise it can cause a continuous rocking in and out of the floor. The Current feedback circuit when set properly allows the car to hold zero speed. One of the constant failure in older MCEs are the crappy little Aromat relays used in the speed selection circuits. There have been many good ideas presented here and I do recommend verifying the HW brake is set properly even if it means tearing it down, cleaning, de-glazing the shoes, and lubricating all pins.
