Two problems related to front suspension lower ball joint have been reported for the 1998 Mercury Grand Marquis. The most recently reported issues are listed below.
Problems with upper and lower ball joints and tie rods. The parts were replaced, some of them twice. Ford put ungreased parts on. Eventually they dried out again and started squeaking. If not replaced they would possibly break which could cause the driver to lose control, possibly causing injury or death. The front brakes were resurfaced.
The inner and outer tie rod ends have been replaced as well as the upper and lower ball joints.