One problem related to front suspension hub has been reported for the 1999 Mercury Sable. The most recently reported issues are listed below.
Car was two years old when purchased, and had 60k miles. I noted that car would shake, especially during braking. I also noted that vehicle pulled to one side during braking. I took car to shop and found that the brake discs had to be turned due to warpage. (I was told that this was common on these vehicles, including tuarus') this eleviated most of the problems, but was told that the tie rods, and tie rod ends were wore out and had to be replaced. I personally looked at the original tie rods after they were replaced and noted that they were wore out. This problem could have possibly resulted in premature braking and lose of control of the vehicle. There was a notable difference in the braking distance and ability to control vehicle at higher speeds. I still have the original tie rods, and ends.