GMC 2008 Savana Van Owner's Manual page 326

6. Remove all the wheel
nuts.
CAUTION:
{
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the vehicle.
In an emergency, you can use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get all
the rust or dirt off. See Changing a Flat Tire
7. Take flat tire off of the mounting surface.
on page 5-78.
5-86