High Pitched Squeal

If the noise changes when you apply the brakes hard, it's a brake problem. It could be that the rotors were not machined correctly ( even new rotors ). When this happens, the rotors will squeal unless you press hard on the brakes. With the brake work, who did the machining of the rotors and what brand of pads were installed?

I have the same problem on my Freestar 2006. Check Ford's recall 04v446000 and this link http://www.allworldauto.com/comments/viewthread.php?cid=618504

it is the wheel bering sensor that you can't change unless you change the whold wheel bearing around $200.00 to do it yourself each you just have to figure out which one is bad.

The front wheel bearing and hub is a common problem on these vehicles, and they do emit a high pitched squealing noise, especially when hot. The right or passenger side usually fails first.