Ford Grand Marquis Owner's Manual page 195

Aluminum wheel
The center wheel ornament
Remove the center ornament from the wheel
with the tapered end of the wheel nut wrench
by inserting it under the notch, and rotating the
handle and then prying against the wheel.
Install the center ornament on the wheel and be
sure it is snapped into place all the way around
using the palm of the hand or a rubber mallet.
196