97 Grand Am Brakes whistle and grind. Why?

Squealer tab in contact with rotor? Small stones trapped ? Malfunction not allowing full release? Maybe you ride the brake ? All city driving ? dry seal in front hub ? Splash shield in contact with rotor ? Your best bet is return to where you purchased the calipers for a recheck. If you have premature failure ? you need someone who can diagnose. Your GM dealer would love to help if the place you went is not available due to your circumstances.

Usually if they begin to squeak, it's due to buying the cheaper brake pads. If they are grinding, like metal on metal, I would get in there and inspect your front brakes. Something is not right. I have had a bad master cylinder where one side would lock up. If your car is not pulling left or right, I doubt you have one side locked up. But get in there and check things out. New brakes and calipers should not be making noise like that. One thing that is typical on most vehicles is if you leave it parked for quite some time, the rotors will get a thin layer of rust on them. If you have not driven your car for a couple of weeks, you may have to drive it for a few miles before you get rid of the thin layer of rust. When that occurs, they will grind for a bit until the rust is gone. If you have not parked the car for a while, those sounds should not be occurring.

As aggressive a lining possible is what those are specified to have , because the weight distribution of the vehicle makes brake bias like 70/30. The fronts do all the work, all the time. Your rust issue, although possible in strange conditions, would be gone in a few miles, just driving. Calling it a whistle and a grind means take it apart and find out. It is expected to make some noise, but if your last set of brakes were different and lasted alot longer, and did not have noise, you want immediate answers. they are the one real thing able to stop that car. See if the pads used are at least as aggressive as the bendix part supplied to meet OEM, since they are the likely designer and builder for the original. That's what we always did when we got wishy washy answers and the manufacturer was questionable. some calipers may have unknown brand pads loaded in them at a rebuilder, lets say. You may have to upgrade. But taking them apart to see what did happen will still be your first step. Hope it's just a stone.