Replacing toilet bowls requires matching manufacturers as tanks and bowls from different sources are not always interchangeable. After securing the correct bowl, turn off the water supply valve and drain as much water as possible before proceeding. Use a sponge to soak any remaining water from the tank, disconnect the supply line and unbolt the tank from the bowl for easier removal.
Toilets are heavy and difficult to remove without help. Since the bowl and tank require separation for replacement of the bowl alone, it makes sense to separate them before removal. Any water left in the tank leaks onto the floor as the connections are loosened, so you should have a collection of old towels on hand to catch leaks.
Closet bolts hold the old toilet to the floor. The removable caps provide access to the nuts. Once they are unscrewed, the old bowl lifts out of place. Remove the old ring and add a new one before replacing the bowl. Adding thick flooring, such as ceramic tile to the bathroom, often necessitates the addition of a riser to the toilet flange. Corroded toilet bolts require replacement when reinstalling the toilet.
When installing the new bowl, over-tightening any bolts can cause cracks in the porcelain. The bolts should be snug against the rubber washers to prevent leaks.