Begin by preparing your workspace. Lay down old towels or a tarp around the base of the toilet to absorb any spilled water and protect the floor. Turn off the water supply to the toilet using the shutoff valve located on the wall behind it; turn it clockwise until it stops. Flush the toilet to empty the tank. Use a sponge and a bucket to remove any remaining water from the bottom of the tank and the bowl. This prevents messy spills when you move the toilet.

Disconnect the water supply line from the bottom of the toilet tank using an adjustable wrench. Have a small bucket or rag ready to catch drips. Next, use a putty knife or flathead screwdriver to gently pry off the decorative plastic caps covering the closet bolts at the base of the toilet. Use the wrench to remove the nuts from the closet bolts. With the bolts free, gently rock the toilet to break the wax seal underneath. With a helper, lift the toilet straight up and away, then carefully set it down on the prepared old towels or cardboard.

With the toilet removed, you will see the old wax ring and the broken flange. Immediately stuff a large rag into the drain pipe opening to block sewer gases and prevent tools from falling in. Use a putty knife to scrape all of the old wax off the flange and the bottom of the toilet horn. Dispose of the old wax. Inspect the flange to confirm the damage. Use a screwdriver, hammer, or pry bar to remove the screws holding the broken flange to the subfloor. If the flange is glued to the pipe, you may need to carefully break it apart with a hammer and chisel to remove it. Be careful not to damage the drain pipe.

Now it's time to install the new toilet flange. Since the drain pipe is PVC, you will use a PVC flange. First, dry-fit the new flange to ensure it sits level and flush on top of the finished floor (the tile). If the flange sits below the floor level, you must use flange extenders or a taller flange. Once fit is confirmed, apply PVC primer to the inside of the flange hub and the outside of the drain pipe. Follow immediately with an application of PVC cement to the same surfaces. Firmly push the flange onto the pipe with a slight twisting motion and hold for 30 seconds. Align the flange so the closet bolt slots are parallel to the back wall. Secure the flange to the subfloor by driving corrosion-resistant screws through the holes in the flange ring into the wood subfloor below.

Insert the new closet bolts into the slots on the newly installed flange, sliding them into position so they are parallel with the back wall. Place the new wax ring either directly onto the flange, centered over the opening, or onto the horn (the outlet) on the bottom of the toilet. Press it gently to make it stick. Carefully, with your helper, lift the toilet, positioning it over the flange and guiding the closet bolts through the holes in the toilet's base. Lower the toilet straight down onto the ring. Press down firmly on the toilet bowl to compress the wax ring and create a seal. Do not twist or rock the toilet once it is set.

Place the plastic retainers, metal washers, and nuts onto the closet bolts that are now sticking through the toilet base. Use an adjustable wrench to tighten the nuts. Alternate between the left and right nut, tightening each one a little at a time to apply even pressure. Tighten until the toilet is stable and does not rock. Be very careful not to overtighten, as this can crack the porcelain base. If the closet bolts are too long, you can trim the excess with a hacksaw before putting on the decorative bolt caps. Finally, reconnect the water supply line to the fill valve on the bottom of the tank, hand-tightening first and then giving it a final quarter-turn with the wrench.

Now for the final test. Slowly turn the water shutoff valve counter-clockwise to turn the water back on. Listen for the tank to fill. Check the supply line connection for any drips. Once the tank is full and the fill valve shuts off, flush the toilet. As the water rushes into the bowl and down the drain, use a flashlight to carefully inspect the entire base of the toilet where it meets the floor. Look for any signs of water seeping out. Use a dry paper towel and wipe it around the base; it will show even the smallest amount of moisture. Flush the toilet several more times and continue to inspect for leaks.