1993 Buick Roadmaster Owner's Manual - Page 226

If a Tire Goes Flat Changing .aFlat Tire I!\ CAUTIO1 can slip off the jack and roll over you or othepeople. You and they could be badly injured. Find a level place to change your = prevent the vehicle from moving: 1. Set the parking brake firmly. 2. Put the shift lever in Park), 3. Turn off the engine. To be evenmore certain the vehicle won't move. you can put chocks at the front and rear of the tire farthest away from the one being changed. That would be thetire onthe other side o the f vehicle. at the otmosite end.