To the person wanting to remove a motor from a Junior, one of the most useful things about the Junior was the fact that the same motor casings were used from 1959 until around 1980, and then continued with a design change to the carbon brush recess until production ended in the later part of the 1980's. Because of this, you should be able to easily find another motor, and then remove yours with brute force, such as a hammer. Once it is out, you can soak the tight screws in WD40 and then removes them with a set of locking grips like a Mole Grip. As long as the orange gasket around the fan is in good order, you will only need silicone if you were to take out the front mounting plate, as silicon would be needed to seal that part to the hood- but removal is something which you would rarely need to do.
