1996 Buick LeSabre Owner's Manual - Page 220

Getting under a vehicle when it is jacked upis dangerous. If the vehicle slips off the jack,you could be badly injured killed. Never get under or a vehicle when it is supported only by a jack. NOTICE: 4. Position the jack and raise the jack head until it fits firmly on the ridge in the vehicle's frame nearest the flat tire. Do not raise the vehicle yet. Put the compact spare tire near you. Raising yourvehicle with the jack improperly positioned will damage thevehicle or may allow the vehicle to fall off the jack.Be sure to fit the jack lift head into the proper location before raising your vehicle.