How To Install A New Toilet Tank Gasket

9 July 2015
 Categories: , Blog


If you notice leaks coming from your toilet tank after flushing, a toilet tank gasket likely needs replacing. The toilet tank commonly has two gaskets that connect the toilet bowl to the tank making a tight seal that helps the toilet flush quickly. However, rubber deteriorates after thousands of flushes, which breaks the seal.  Here are some tips to fix a leaky toilet gasket.

Turn Off Water and Empty Tank

Turn off the water to the toilet at the valve usually located behind the toilet. If you can't find a toilet shut off valve, turn off the house's main water supply and place towels on the floor.

Set the toilet lid in a safe area on towels or a quilt. Flush the toilet to drain excess water and clear remaining moisture with a sponge. Remove the water supply line by hand or with a crescent wrench.

Remove the Tank from the Base

Turn an overhead slot screwdriver left to remove the two bolts connected by a nut under the tank. Stabilize one nut with locking pliers to keep it from moving while you remove the other. The pliers will keep spinning until they reach the wall and lock the nut in place. If the bolts are rusted, spray them with a rust remover and let it stand six to eight hours.

Remove the bolts and carefully lift the toilet tank off the base, placing it on padding. Get someone to help you lift the tank if it is heavy. Set the tank on towels or padding on its back.

Replace the Gasket

Remove the old gasket and clean residue using a rag dampened with rubbing alcohol. Insert the new gasket in the opening with the end of the cone facing out. Set the tank back on the bowl pressing down to secure the bolts. Even if the rubber washers on the bolts aren't damaged, replace them with new ones to help avoid problems later.

Slide them under the head of the bolts and drop the bolts in the tank holes. Insert the plastic washers on the screw threads below the tank and the nuts. Tighten one nut by hand while anchoring the other with locking pliers.

Keep tightening the nuts until the toilet is steady. Be careful not to tighten the nuts too much or it might crack the tank. Place the lid back on the tank and turn the water back on to test for leaks.

Sometimes, replacing the toilet tank gasket will stop the leak when you flush. If your repairs fail or you spot other leaks, you may need a plumber, like those at Watson Plumbing, to find the problem.


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