Turn off the water to the toilet at the water shutoff valve. Flush the toilet to remove as much water from the tank as possible. Use a sponge and a bucket to remove the remaining water from the water tank.
Disconnect the water line from the flush/float valve. Use a pair of channel lock pliers to get the hose started. Once the hose has been started, it can be unscrewed by hand.
Use a pair of channel lock pliers to remove the nut that connects the fill valve to the toilet tank. The retaining nut is located under the tank. After the nut is removed, pull the old fill valve out of the water tank.
Use a tape measure to measure the height of the overflow tube in the center of the water tank. Adjust the new float/flush valve to the measured height by holding the base of the new valve and twisting the top.
Attach the rubber washer to the new float/flush valve, and insert the new valve into the toilet tank with the threads going through the hole in the bottom of the tank. Thread the lock nut over the threads to secure the new float/flush valve to the toilet tank.
Connect the rubber fill tube from the new float/flush valve into the overflow tube with the supplied clip. Connect the water line to the exposed thread of the float/flush valve below the toilet tank.
Turn the water on to the toilet, and fill the water tank. Adjust the float on the new float/flush valve as necessary to get the correct water level. To adjust the float, pinch the spring clip and move the float up or down.
Turn the water shutoff valve off to the toilet. Flush the toilet to empty the toilet tank.
Use a pair of pliers to unscrew the rod arm from the valve. The float ball is connected to the rod arm. Grasp the arm with pliers to close the valve. Turn the rod arm counterclockwise to remove it.
Thread the new float ball to the new rod arm. Thread the rod arm into the water valve, and tighten it with the pliers. Do not over tighten as this may cause the plastic water valve to break.
Turn the water back on to the toilet. Adjust the water level as necessary by bending the rod arm.