When you are replacing your tub faucet cartridge, the cartridge will not always come out with ease. Sediment and corrosion will sometimes lock the faucet cartridge inside the plumbing. You can remove a stuck faucet cartridge with a special cartridge-pulling tool available at home improvement centres and some plumbing supply houses. The process will be slow but you want to remove the stuck cartridge without damaging any of the copper plumbing.
Ensure that the retaining clip is out of the cartridge. This clip secures the cartridge to the faucet plumbing. Use a pair of needle-nose pliers to pull the retaining clip off the cartridge.
Turn the thumbscrew on the top middle of the cartridge-pulling tool counter-clockwise with your fingers. Place the cartridge-pulling tool over the front portion of the faucet cartridge. Twist the cartridge-pulling tool clockwise until the tool locks over the cartridge.
Turn the thumbscrew clockwise until you cannot turn the screw. Use a socket wrench to tighten the nut on the centre of the cartridge-pulling tool. Pull the tool and the cartridge straight out of the faucet plumbing. You may have to use some force and slight twisting to accomplish removing the cartridge.
Pull on the end of the cartridge with a pair of vice grips. Most often the faucet cartridge stem will come out leaving the remaining portion of the cartridge inside the faucet plumbing.
Pour some vinegar into the remaining faucet cartridge to loosen and dissolve any calcium deposits. Insert a tap inside the faucet plumbing to cut threads into the remaining portion of the cartridge. Most tub faucet cartridges will accommodate a ½-inch 20 pitch tap. Use a tap that is slightly larger in diameter than the cartridge stem. You will also need a 6-inch long case-hardened bolt to fit the threads after tapping.
Cut the threads into the cartridge ½-inch deep. Use care when cutting with your tap; although the cartridge is a soft material you can still break your tap. Turn clockwise a half turn and then turn counter-clockwise a quarter turn. Continue tapping until you have ½-inch deep thread and then pull your tap out of the cartridge.
Thread your bolt into the fresh cut threads in the cartridge until the bolt is hand tight. Use a socket wrench to continue tightening the bolt until the cartridge inside starts to turn. Once the cartridge turns, grab the end of your bolt with a pair of vice grips and pull the stuck cartridge out of the faucet plumbing.
Tap and die sets are available at home improvement centres. Use only case-hardened bolts when using the tap method.
Do not tap more than a 1/2 inch into the remaining cartridge. You do not want to damage any of your copper plumbing pipes.