Hi guys just wondering... My boat trailer has hubs with the discs on them for the brakes, Im going to be changing the bearings and noticed the packs with the hubs and bearings are real cheap but they are the hubs without the discs are the hubs connected to the discs or are they removable? Cheers omally.... Only thing I cleaned up my discs and with the new pads makes a Lil grinding noise I'm hoping it goes away heaps better than what it was... Wouldn't they rust up anyways if not in use I know my rotors on my car sometimes rusts up if not driven.... Is it normal or?