2003 GMC Sierra 1500 Pickup Owner's Manual - Page 470

4. Remove all the wheel nuts and take off the flat tire. 1 5. Remove any rust or dirt from the wheel bolts, mounting surfaces and spare wheel. Rust or dirt on thewheel, 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 t o to, get all the rust ordirt off. Neve, clse oil or grease on s d s or nuts. If you do, the nuts might come loose. Your wheel could fall off, causing a serious accident. 5-95