Has anyone ever had an issue with the brakes being over pressed in the rear and grinding out the inner brake pads? I changed out the pads and calipers, bled the entire system twice, rebuilt both calipers, and switched out the caliper brackets because of the seized slider bolts. Now, after doing all of this, I finally getting my car together after a month, ITS STILL GRINDING!!! I'm furious! I've never had brakes be such a massive PITA. Now I have to pull it all apart again tomorrow for the 4th time this week to figure out what the hell the issue is. Does anyone have any ideas?

Rear calipers I am guessing, maybe try emergency brake shoes not adjusted correctly.

What do you mean by grinding. The rear caliper piston on Mustang at least on my 2006 has to be spun in all the way and then put on the car to self adjust?

Is the grinding noise only there when you apply the brakes?

Its really not a grinding but that's the only word I could come up with to describe it. It is constant weither I apply the brakes or not. It made the same noise before until it completely wore out my inside brake pads and put nasty groves in the rotor. I completely redid the rear brakes, re-placed the pins that seized. And it still makes the noise. I'm going to check next weekend for wear on the brake pads. If nothing, it's on to replacing the bearings

When you take the tires off and have it on jack stands have some one give it some gas to see where the noise is coming from. If it's a bearing or anything around the Brakes you'll hear it. Does it get worse as you hit the brakes?

Not noticeably. And the tone of the sound doesn't change no matter the speed I'm going. It stays consistent. Which makes me think it isn't the brakes. But the sound is the same as it was before the brakes blew up. I figured that was because the slider bolts were completely seized. Now that those are replaced, and it's still doing it, I either didn't fix it right, or something like the bearings are going. The car has 220,000km on it, or 150,000 miles, so it wouldn't surprise me if it was the bearings. I'll have to put it on the lift this weekend and see if I can find the source of the noise.

I don't know why I didn't think of this before, but brakes shouldn't make any noise if they are being pressed into the rotors. Not until they are worn out at least. So I believe the bearings are the issue.

Edit*

Had the car up on the lift. Definitely the rear bearings and my left axle seal is toast too. Might have had something to do with the 1-inch spacers the previous owner had on...