Ford Mustang Owner's Manual page 197

Install the wheelcover on the wheel with the
valve stem in the wheel matching the hole in the
wheelcover. Push by hand on the outside edges
of the wheelcover until it is snapped firmly in
place on the wheel.
Install the exposed lug nut wheel cover onto the
wheel with the valve stem in the wheel
matching the hole in the wheel cover. Push the
ornamental lug nut covers over the lug nuts by
hand, and secure the wheel cover by tightening
the lug nut covers clockwise with the wheel lug
nut wrench.
Anti-Theft Wheel Lug Nuts (If equipped)
The aluminum wheels on Mustang 4.6L engine
vehicles are secured with locking lug nuts. One
of the lug nuts on each wheel must be removed
and installed with a special key. The key and a
registration card are attached to the lug wrench
and stored with the spare tire. If you lose the
key, send the registration card to the
manufacturer (not to the dealer) to get a
replacement key.
NOTE: If entire lug wrench/lug nut key
assembly is lost, see your nearest Ford
or Lincoln-Mercury dealer who has
access to a master set of keys.
NOTE: DO NOT USE A POWER IMPACT
WRENCH ON THE LUG NUT KEY.
The anti-theft lug nut and key
199