These are the oil bath, brushed motors.
Sorry for the euphemism. By “lost” I meant the thrusters stopped working. In one instance I could not connect with the ROV until I eliminated the thruster from the ROV.
Everything operates with 3 thrusters, though the ROV was designed for 4. I eliminated the lateral thruster as the the least required for operation.
I like your suggestion to attempt to repair the motors. I suppose I really don’t have anything to lose by taking one apart. My only concern is the oil bath if the thruster is emptied. According to the literature, they are filled in a vacuum and topped off as needed by a rather lengthy process. I’ve done this twice now, replacing the oil compensation tubes.
I agree mixing brushed & unbrushed will not work when the thrusters are paired, but individually they should be okay. The ESC is my primary concern.