Slight Grinding Sound When Braking

[spyder_m_2000]

I have a 2005 GMC Sierra 5.3 4x4 extended cab. I recently replaced the front pads and had the rotors turned. The rear breaks were changed at the same time as well as new tires. I hear a faint grinding sound when I brake but only when I am going over 60 mph. I cant seem to hear it at slower speeds. It sounds like it is coming from the front passenger side. I can also feel it barely in the steering wheel. My question is could it be the wheel bearing or maybe the half shaft is starting to go bad. I only hear it when I am braking at high speeds and all the brakes are new. Also could there be air in the line that might cause it to make a sound like that. I am about to tear it all apart again and would like to know if there is anything else I should look for.
Thanks