I'm trying to show my son how he can change a flat tire should it ever
happen to him and I've got a strange problem - the wheel will not come off.

He has an 89 Cutlass Ciera.
I removed all 5 lug nuts, the car is in park, the emergency brake is off,
the wheels are braced and the car is jacked up and the wheel is clear from
the pavement.
The wheel refuses to come off the lugs for some reason.  I tried wiggling it
in all directions, kicking it, trying a wooden mallet from the inside of the
wheel well...and nothing.  It just will not come off.

Ideas?  I haven't tried the other wheel(s) yet.

Thanks,
Walter