GMC T-Series 1999, Owner'S Manual, Page: 180 / 344

yellow blue
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CAUTION:
If you work on a pressurized tire mounted on a
damaged wheel, the assembly can expand with
explosive force without warning. You and others
nearby can be badly injured. Don’t work around a
tire that has air under pressure in it when its lock
ring or side ring might not be properly seated.
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.