The toilet stool, or bowl, is the part of the toilet that holds the sewage and connects to the sewer pipe to carry away waste. Because it holds the weight of most of the toilet, as well as everyone who uses it, the toilet stool is subject to a lot of pressure. This can lead to a cracked bowl. The best way to repair a cracked toilet stool base is by replacing the whole bowl. Fortunately, the process isn't difficult, even for a first time do-it-yourselfer.
Turn off the water supply. The valve is usually located on the wall, just beneath the toilet tank. Turn clockwise to shut off the water.
Flush the toilet to remove the water. Clean up any remaining water with a rag and sponge.
Remove the water supply line to the tank.
Unscrew the bolts that hold the tank to the bowl. You can use a screwdriver to hold the head of the bolt in place as you unscrew the bottom with a wrench.
Lift the tank from the bowl and set aside.
Remove the plastic caps and loosen the bolts that hold the toilet bowl to the floor. Gently rock the bowl back and forth until you feel it loosen.
Lift the bowl up and out of the way.
Clean off any remnants of the old wax ring from around the toilet flange (the plumbing exit in the floor). Insert new flange bolts into the flange ring.
Turn the new bowl upside down. Press a new wax ring around the water exit in the bottom of the bowl.
Lift the new toilet bowl up and over the flange. Pay close attention to this part, because not only do you have to make sure that the wax ring and toilet outlet line up with the flange in the floor, but you must make sure that the flange bolts poke through the holes in the bottom of the bowl.
Press the toilet firmly in place to help ensure a tight seat. Screw on the nuts and plastic and metal washers onto the flange bolts. Tighten the flange nuts hand tight, then tighten one additional turn with a wrench.
Gently place the tank back on top of the bowl, making sure to line the cone gasket at the bottom of the tank with the inlet on the bowl. Drop the tank bolts and washers through the hole and tighten as you did with the bowl bolts above: first hand tight, then one turn with the wrench.
Wrap the water inlet on the underside of the toilet with plumber's tape. Then reattach the water supply.
Remove the toilet seat and lid from the old toilet stool base. Drop the bolts on the lid through the two holes at the back of the new bowl. Tighten with the wing nuts on the underside.
Caulk around the base of the toilet.
Turn the water supply back on.
Flush the toilet and check for leaks.
Some plumbers like to run a thin line of plumber's putty along the bottom of the bowl before they reseat it.
Overtightening the bolts could crack the porcelain.