I have several Black & Decker corded mowers, all 120V, 12A, 18". I had to replace brushes on one, so I decided to remove the magnet shell in order to give the motor a good cleaning. After re-assembly the armature would not spin freely. I double checked ALL places where it could bind or rub on something and found absolutely nothing. It appeared to be some magnetism between the PM and armature. I decided to take another B & D (that worked well) and remove its magnet, just to compare things. The same thing happened on this one. I re-assembled it VERY, VERY CAREFULLY. Nothing was rubbing, only a magnetic force that prevented it from spinning really freely. When these two mowers were re-assembled, the brushes just sparked because they could not overcome the drag on the armature. Does anyone have any thoughts on this? Thanks in advance.