need perfect pass help

If you can get the four Phillips head screws out of the motor without twisting them off, you're on your way to repairing it. Make sure you have a proper fitting screwdriver before you try. Maybe put some penetrant on the threads at the other end of the motor and let it soak in for a couple of days.
Once you get the end cover off the motor, press out the armature, then clean the corrosion off the stator magnets and the armature with a nonmagnetic wire brush. (I use a brass brush that looks like a big toothbrush)
Blow out with high pressure air if possible. Your problem was caused by the motor getting wet, be it from condensation or otherwise.
Art