1. Disabling the Water Supply
Initially, remove the lid from your toilet tank, allowing you to disable the water supply by turning the shut-off valve clockwise. Hold the flush lever down to drain as much water as you can out of the tank, and use a towel or sponge to get rid of any remaining water.
2. Disconnect Toilet Attachments
Disconnect the water supply tube or hose from the tank, the flapper chain from the tank lever arm and the refill tube which will be connected to the top of the overflow pipe. Apply penetrating oil to bolts positioned beneath the tank, and unscrew them to detach the tank from the bowl. Be careful to avoid getting oil on surrounding fixtures such as towel warmers, radiators or bathroom vanities.
3. To the Tank!
Using an adjustable wrench, you can loosen and eventually remove tank bolts. This will allow you to lift the tank from the bowl and set it to the side, making it far easier to work on. The locknut which is securing the flush valve to the tank should be unscrewed using a plumber’s wrench, enabling the old flush valve to be removed.