GMC 2004 Savana - Manual (Page 333)

5. Remove all the wheel
nuts, and take off the
flat tire.
6. Remove any rust or dirt
from the wheel bolts,
mounting surfaces
and spare wheel.
{ CAUTION:
Rust or dirt on the wheel, or on the parts to
which it is fastened, can make the wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
the 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 you need to, to
get all the rust or dirt off.
5-87