Things You'll Need
Moen's cup-seal diverter, sometimes referred to as a gate diverter, serves the dual purpose of directing water to the bathtub and, when the diverter is actuated, routing the water to the showerhead. Within the assembly is a cup seal designed to prevent water from exiting the tub spout when the diverter is operated. It is for this reason that a leak from the tub spout when the shower is in use is attributed to a worn seal. The seal and diverter are within a single assembly and cannot be repaired. Replacing the assembly, however, is a straightforward job.
Grasp the base of the diverter assembly with channel pliers.
Rotate the diverter assembly in a counterclockwise direction until it detaches from the water supply pipe.
Remove any old plumber's tape from the threaded tip of the water supply pipe by scrubbing the tip with a wire brush.
Wrap the threaded tip of the water supply pipe with new plumber's tape.
Position the new diverter assembly onto the tip of the water supply pipe. Rotate the assembly in a counterclockwise direction by hand to ensure that the threads of the pipe align with the threads inside the assembly.
Wrap the jaws of the pliers with masking tape to avoid scratching the finish of the new diverter assembly.
Turn the diverter in a clockwise direction with the pliers until the back of the diverter rests flush against the shower wall.