How to replace armature

[Rich]

I'm getting sparks flying from the copper of the armature and brushes and now I'm only getting half speed. I started to take the armature out but I couldn't get it out. Does anyone know how to get it out so the armature can be replaced. I might be missing a step to get it out. Thanks

[Darren]

Please let me know if you have a solution. Mine is doing the exact same thing.