without touching the brakes you're hearing this? Bring it back. I had a terrible grinding noise that would randomly happen just coasting down the road then it turned into a full-time problem. They replaced the front pads (not rotors) and all was good. I believe it's always in contact but there's probably an imperfection in there.

__________________
'08 X5 3.0si - Alpine White / Saddle Brown interior
Specs: Sport Pkg, Premium Pkg, Tech Pkg, Comfort Access, Aero Kit, Style 433 staggered 20s on Conti DWS
Mods: Carbon 35 tint, LED angel eyes, GP Thunder 7500k fogs, H&R 20mm/25mm spacers, clear reflectors, gunsmoke-tinted taillights
Coded: Digital speedo, windows/sunroof/tailgate close via keyfob

X5 pics at Flickr