Mercedes-Benz 2004 C-Class Wagon Operator's Manual page 323

Mounting wheel cover (Canada only)
!
The wheel cover does not fit the
Minispare wheel.
Wheel cover on vehicles with steel rims
(Canada only)
Practical hints
Flat tire
Position small wheel cover opening
over tire valve and press wheel cover
against wheel rim.
Now press (do not hit) opposite side of
wheel cover against wheel rim until
seated.
Make certain that the springs of the
wheel cover are firmly seated in the
outer rim of the steel wheel.
323