The most difficult part of a toilet to repair is the tank-to-bowl kit, which consists of the bolts, washers and gaskets that connect the water tank to the top of the toilet bowl.
Fortunately this part of the toilet usually lasts a long time. So, if your toilet is leaking from the bolts and gaskets that connect your toilet tank to your toilet bowl, it is probably a good idea to replace your toilet with a newer, more efficient model.
If you dont want to replace your toilet, and just want to repair it, this can be done also. The first step is to close the toilet shut off valve that supplies water to the tank and to flush the toilet to get rid of as much water as possible from the toilet tank. Then use a sponge, or something similar to soak up the rest of the water that remains at the bottom of the tank.
Once you have a relatively dry toilet tank, you can begin by disconnecting the toilet supply line. Then remove the nuts from the tank bolts. The nuts are located underneath the toilet tank, where the bolts go through the toilet bowl. Here is a picture of the toilet tank bolt nuts:
You can use a small crescent wrench, adjustable wrench, pliers, a nut-driver or a socket set to remove the nuts. Occasionally the nuts will be very rusty and corroded and may need to be cut off using a hacksaw, dremel tool or an angle grinder. *Be very carefully when doing this, as it is easy to damage the porcelain part of the toilet when using any tools on any part of the toilet! The nuts should spin off normally, counter-clockwise.
The bolts above have a flat head with a slotted fit, so that you can hold the bolts still using a large slotted screwdriver. This can be tricky though and having another person to help can assist you if you are not very dexterous with tools. I usually do it by using one hand in the tank holding the slotted screwdriver into the slotted bolt head, and then with the other hand I use a nut driver on the underside of the tank where the nut is. I hold back on the bolt, while spinning the nut driver and loosening the nut.Most toilets have two bolts holding the tank on, but some models will have three.
If you have a model with three make sure you buy a tank-to-bowl kit that has three bolts and nuts! Or buy two kits so that you can use an extra set of nut, bolt and washers.Once you have the nuts off, you can push the bolts through from the bottom up. Then carefully remove the bolts from inside the tank.
Be very careful, as once you remove the bolts, there is nothing holding the tank in place and it could easily fall over and shatter and even possibly cause injury! Now the tank can be removed from the bowl and carefully set down on a towel or something. It is better not to set the tank down on a hard surface such as tile, as the porcelain can easily crack or shatter on a hard surface! It has happened to me before!Now you can remove the rubber gaskets from the bolt holes, and the flush valve hole. Make sure you use a similar sized gasket as the old one.
There are many different gaskets that connect the flush valve of the tank to the flush port of the bowl. If you cant find an exact matching part for your toilet model, then I usually recommend using an American Standard tank to bowl gasket. It fits most models as kind of universal fit. Here is a photo:
Now is usually a good time to replace the flush valve if needed, since the flush valve can only be replaced while the tank is off. Install the new gasket on the bottom of the tank flush valve. Insert the bolts into the tank, making sure to put on the flat black washers so that they seal between the bolt head and the inner tank porcelain.
Then fit the tank back onto the bowl and carefully thread on the nuts and washers onto the bottom of the tank/bowl. It is best to thread the nuts a little at a time, so that the tank is sitting level and even on the bowl. Much like threading lug nuts on a tire.Once the nuts are snug and the tank is sitting firmly on the bowl, connect the water supply line and turn the water on. If you have any leaks, then either the rubber gaskets are not installed in the right place, or the nuts and bolts arent tight enough. Also, do not over tighten the nuts and bolts, or you can crack the porcelain on the tank or the bowl.
You should have no leaks coming anywhere from the tank once the water is turned on. If you have leaks or get frustrated anywhere along the process, it is best to call a professional plumber, as this job is one of the most advanced toilet repairs!