Shut of the water at the main valve. Turn the handle of the valve clockwise to turn it off. The shut-off valve is typically located on the pipe at the back of the toilet. Some older homes may require that you located and turn off the water to the entire house.
Place a bucket under the tank of your toilet where the water feed line is located.
Remove the water feed line from the underside of the toilet. Loosen the retaining nut at the top of the line by turning it counterclockwise. Be careful of the water that will release from the tank of the toilet to the bucket.
Pull the old valve up and out from inside of the tank.
Drain the rest of the water from the tank into the bucket. It will flow freely once the nut is removed.
Wipe any excess water and debris from the interior of the tank with a dry towel.
Insert the new valve at the hole from which you removed the old valve. Twist the valve clockwise to secure it in place. The float of the valve should not be in contact with any wall or object in the toilet.
Insert the overflow tube into the overflow pipe. The overflow pipe sticks out of the side of the valve and is wide enough to insert the overflow tube that is in your tank.
Insert the water feed hose back into the bottom of the hole from which it was removed. Tighten the retaining nut by turning it clockwise. This will secure the hose in place.
Turn the main water valve on by turning it counterclockwise.