Have just bought a new 2004 GF Marlin Disc and the back brakes are really noisy whenever they are used. THought that they may need to be worn in so have done a few rides on the bike and used the brakes a fair bit to see if this would wear them in, however the back brake is still very noisy. Front brakes are fine.
Had a look at them and "visually" they look ok, but being a novice at disc brakes i am not really sure what i should be looking for?
Try cleaning the brake rotor with isopropyl alcohol.
(Also, try a forum search for "disc brake squeal" or similar topics.. I'm pretty sure there's been a past thread on this which should yield more ideas)
