Well, not actually rebuilding it but more tearing it apart and putting it back together ... (for polishing reasons) so how hard is it to put them back together right ... Im asking because I am fairly certain sanding this will lead to gritty aluminum gettinto it somehow.

 

Opening it up reveals bearings. I've taken mine apart before to grease it. I didn't remove the guts, but I can at least tell you that it's safe to open it up and see whats going on and if you can remove what you see.