Brake grinding noise
 

I have a 1995 Ram 2500 with 73000 miles. When depressing the brake there is a loud grinding noise which seems to be coming from the right front. Upon inspection, the rotors on both sides is smooth with the medal indicator not even close to the rotor. Looked at the rear drums and the same thing. They look good.
What could possibly be causing this grinding noise only when braking?:confused: Thanks