'99 F150 4x4, 90k miles, probably original brake pads. I've put 40k on the truck and have not re-packed wheel bearings yet.
Could this be the source of the noise? Started about a month ago and seems to be getting slightly louder/more pronounced. Audible only when coasting (and the engine is not loud, so it's not masking the noise).

 

As the pads wear and get thinner they can sometimes cause that kind of noise. Like metal rubbing agianst the rotors when you are not applying the brakes. Sometimes you can feel it in the pedal when you first apply light pressure. Prob. can stop it with a good front brake job ( turn rotors and new pads.) Always a good idea to service the front hubs and repack the bearings in a 4x. They are a real expensive fix if they seize or go bad.

 

Thanks, Pestco1!