Metallic Squeal hearing
 

I am experiencing a Metallic Squeal while I was driving. It is a high-pitched noise and it stops when I push the break. This vehicle is one of my friend's and she handed over this to me for a week for taking care of it because she is on aboard vacation. I asked her about this and she said that this began nearly one month ago. What would be the reason for this?

Could be the calipers or wheel bearings.

if only happens when braking almost always the brake pads. I've re-done all 8 brake pad sets on a pair of client cars that sounded like a bus coming to a stop. take off the pads, put some anti-squeal (it's like thread lock) between caliper and brake pad and reassemble. 'I put that shit on everything'. They say not to use with shimmed pads but if they squeal i use it and it's always worked. There is no magic spray for rotor that actually works.