Turn off the water to the faucet by closing the valves under the cabinet.
Unscrew the nut holding the handle onto the faucet stem with a Phillips screwdriver. If you can't see the screw, it's probably under a plastic cap. Pry the cap off with a slot screwdriver. If the handle is a lever, it is probably held by an Allen nut hidden under the handle. You can remove this with a small Allen wrench. When you remove the screw, lift the handle off the faucet stem.
Examine the valve stem. If you see a small retaining pin or clip holding the cartridge in place, pull it out with needle-nose pliers. If the cartridge is held by a nut, unscrew the nut with slip-lock pliers after first wrapping a rag around it to protect the finish.
Note the orientation of the cartridge in the valve seat, then grip the faucet stem with the slip-lock pliers and pull the cartridge straight out. If it won't come, reattach the handle and use it to pull the cartridge out. If the cartridge is stuck and you see mineral deposits around the edge, soak a rag with vinegar and wrap it around the cartridge. Leave the rag for 10 to 30 minutes, then try pulling it out again.
Examine the O-rings around the cartridge and replace them if they are worn. Pry out the seals from the valve seat with a slot screwdriver and replace them if they are worn. Clean mineral deposits from inside the valve seat with a vinegar-soaked rag. These deposits can interfere with the operation of the cartridge.
Chip off any mineral deposits on the cartridge with a slot screwdriver. If they are hard to remove in this way, soak the cartridge overnight in vinegar.
Shake the cartridge if it comes from a PosiTemp faucet. You should hear a rattling sound, like the sound made by a can of spray paint when you shake it. If you don't, hold the cartridge in one hand and push on the faucet stem. The spool will emerge from the other end. Clean the deposits from the spool and from the inside of the cartridge sleeve, then reassemble the cartridge. Shake it to make sure it rattles.
Purchase a new cartridge if the old one is cracked or too corroded to clean. Cartridges are inexpensive and available at plumbing supply stores.
Push the cartridge back into the valve seat in the same orientation it was in when you took it out. If it has a small arrow on it, be sure the arrow is facing the 6 o'clock position. Replace the nut, pin or clip, then screw the handle back on and turn on the water.
Things You Will Need
- Phillips screwdriver
- Slot screwdriver
- Allen wrench
- Needle-nose pliers
- Slip-lock pliers
- You can buy a special cartridge puller for hard-to-remove cartridges at a hardware or plumbing supply store.
- Some cartridges won't control temperature correctly if they are put in backward. If your faucet delivers only hot or cold water, remove the cartridge, turn it through 180 degrees, and reinstall it.