having problems with my drivers side front brake

hey folks i need some serious help with a problem on my sons car. My son has a 98 ford contour se and when your driving it down the road and hit the brake the caliper is forced into the wheel and it makes an awful noise. I have been working on this problem for a couple of weeks now and frankly I dont know what to do next. I have put a brand new caliper with pins and bushings, rotor was turned, new brake hose, new pads, it still does it. I jacked the vehicle up put it on stands and had my wife start it put it in drive while i was underneath it wathing and every time she let off the gas and put on the brake the caliper would give a little making it rub against the inside of the wheel. I even put the tire that was on back on front and it still does it. I reconfirmed that they sold me the right caliper and they did. any help I sure would be grateful thanks