If you follow some basic instructions, replacing a toilet cistern is not a particularly complicated or time-consuming job. The cistern is one of the main components of a toilet. If it gets damaged or stops working for any reason, it may need to be replaced. The cistern is the component which draws water into the toilet when the flush handle is used. If the cistern is cracked or damaged in any way, it will start to leak, and the only practical way to deal with the problem is by replacing it entirely.
Step 1 - Make Necessary Preparations
Before you begin, obtain a new cistern for your toilet. Dimensions are pretty standard. Which one you pick depends on aesthetics, such as whether you want a plastic or ceramic one. Teflon tape should be available in any well-stocked hardware store, and an adjustable wrench is the only other item you need.
To begin, turn off the water supply to the toilet. You should be able to find a valve nearby, probably beneath the toilet by the wall. Turn this clockwise to disconnect the water supply. Flush the toilet to get rid of any remaining water, and you should find that the cistern does not start refilling. Wipe the area clean before beginning.
Step 2 - Remove the Old Toilet Cistern
At the bottom of the cistern, you should find a water inlet pipe. This should be attached to the cistern by screws. Disconnect this and move it out of the way. The cistern itself can then be removed from the toilet bowl.
You should find that the cistern is attached to the toilet bowl by several nuts and bolts. The fittings come in various sizes, so you should have an adjustable spanner at your disposal to remove them. In some cases, there may be plastic or metal toggle nuts which you can remove more easily. Be sure to remove any washers as well and put the fittings aside somewhere safe where you will lose them. You will need to reach inside the cistern and pull out any bolts and washers when you have removed the nuts.
To physically remove the old cistern, simply lift it out of place once you have removed the connections.
Step 3 - Install the New Cistern
Install the new cistern in the same manner in which you removed the old one. Be sure that it lines up correctly. The cone gasket found on the bottom must line up with the hole at the back of the toilet bowl. Wrap up the inlet of the new cistern using Teflon tape, and then reattach the water inlet hose to the new cistern. Finally, turn the water supply back on. The cistern should start to fill with water again. Be sure to check the new installation for leaks before continuing.