So I have a 98’ Mustang GT and the wire that has the gray rubber hood on it that connects to the top of the alternator to charge the battery had melted off cause me to need not only a new wire but a rebuilt alternator. The wire follows through my engine bay to the fuse box. I cannot seem to get the bolt off that holds the wire down. Can anyone give me some insight on how to get it off or do I need a “back-up” so it doesnt break the plastic fuse box.(Picture provided below)...

Alternator wire to charge battery needs replaced but wont come off