What size of bolts are needed for lower ball joint replacement on a grand prix?

For a lower ball joint replacement on a Pontiac Grand Prix, you typically need 18mm bolts for the joint itself, although the specific size may vary depending on the model year and whether any modifications have been made. It's always best to consult the vehicle's service manual for precise specifications or check the existing hardware before purchasing replacements. Additionally, ensure you're using the correct grade of bolts for safety and reliability.