My pickup is an enormous pile of rusty metal, but that's ok because it brings me places and I love it to death.
anyway a few weeks ago I started to get a sort of light grinding sound coming from the wheels on the passengers side... almost like two rusty pieces of metal lightly rubbing together in time with the rotation of the wheels.
Even when I stomp on the brakes the noise doesn't change, but on occasion when I hit the brakes or hit a bump in the road it will stop for a few minutes.
it started barely noticeable only if I had the passengers side window down and driving near a wall would I hear it echo back faintly, now I can hear it with the windows up and the radio on.
I had it checked out at a shop and they said they couldn't hear it

but they checked out the front brakes and said everything looked fine and I had 1/4 of the brake pads left.
I'm worried it might be a wheel bearing, or worse, and axle. I'm also wondering if it could be the rear drum brakes as a co-worker said sometimes a rusty build up on the inside the drum could produce that noise.
Any ideas?