Brake noise

I have a 2003 F250 4x4 7.3l diesel, it has 115k miles and had the original brakes till last week. at that point I started hearing a metal to metal sound so I bought a new set of front brake pad and proceded to pull the fron wheels, to my suprise 35-40% remained on the front and 50% in rear. cahned pads any ways but (guess what) I still have the noise. any help would be greatly appreciated.

Check all the rotors for scoring, both sides. There may be a tiny pebble stuck behind a pad or in the drum if you don’t have rear disc brakes.

I did not turn the roters and just slapped pads. I did find that the outer 1/8 - 1/4 inch of the rotor surface was flacky/rusty. the truck only get driven aboout 1 week every 6 - 8 weeks.