I guess it is the end of the line for my Kenmore 158 that my (late) mom bought new back in the 60's. I have been using it ever since.
It quit working, I suspected the brushes. Had to take the motor apart to get to them, they were completely disintegrating and the housing they sit on was broken as well, probably from the effort to get the motor apart. So no repair possible, it needs a whole new motor.
I have another Kenmore head that fits into my cabinet, but it is not the same as using my mom's machine. I guess I will keep it on the off chance that I can find another motor for free. (Can't convince DH to spend money on it if I have a head that works - he is just not sentimental like me.)