Brake Disc Rotor problems of the 2004 Lincoln Navigator

There is a distinct shimmy in the steering wheel when decelerating from highway speeds. The shimmy progress' as time goes on. The rotors have been resurfaced twice and changed once.

2004 Lincoln Navigator was purchased August 30th 2004, on its first drive huston from dallas, the rotors heated and warped resulting in serious shimming issues, this was fixed by machining the rotors. Second trip to vermont during christmas holidays from dallas, rootors warpped again and the Navigator was shimming seriously, getting me and my family nervous throughout the 3300 mile round trip to east coast, driving on icy roads and through the mountains. Dealership simply machined the rotors again, they admit that other 2004 models have had this issue but would not replace rotors. I believe that this is bad rotor batch that needs to fixed before family are seriously injured or killed.