I know there's going to be 2 diff outlooks on how this should be done, either just pulling the end cap and replacing the brushes or taken apart and cleaning case and arm free of brush dust. I usualy do the total tear down and clean and solder in the newbrushes myself. I've started running into several lately that want come apart with out a hammer(mostly 2 and 3KOS K machines). The motor shaft seem to be stuck in the bearing at the end of the motor that bolts to the machine. If you do seem to get it apart with the hammer or heating the bearning is now no good. Anyone found a magic trick to these sometimes tricky motor rebuilds??

There are several products on the market that are used to free-up rusted nuts and bolts. I use a product called Liquid Wrench made by Gunk. It is a penetrating fluid that works pretty good. Just give it time to work and that should help your problem.