Step 3 · Remove the Faucet Cartridge
With the handle removed, you'll see the valve stem of the cartridge. There may be a decorative metal sleeve or dome (escutcheon) covering the valve body; unscrew this by hand. Now, you will see a large nut, often called a packing nut or retaining nut, holding the cartridge in place. To protect the faucet's finish, wrap the jaws of a pair of channel-lock pliers or an adjustable wrench with electrical tape. Grip the nut with the wrapped pliers and turn it counter-clockwise to loosen and remove it. Once the nut is off, grasp the plastic or brass stem of the cartridge with the pliers and pull it straight up and out of the faucet body. Note the orientation of any tabs on the cartridge, as the new one must be installed in the same position.