How to Repair a Leaky Cartridge on a Moen Faucet

A single-pull Moen faucet has a cartridge inside the faucet body that eventually may need replacement. The cartridge controls the flow of hot and cold water when you pull the handle. If the faucet is leaking at the base of the handle, the cause is most likely the O-ring in the cartridge. An O-ring kit for a Moen faucet cartridge is available for less than $10, based on 2010 prices.

Things You'll Need

• O-ring kit
• Allen wrench set
• Adjustable wrench
• 2 slip-joint pliers
• Plumber's grease

Instructions

1. Turn off the water supply to the faucet, using the water stops under the sink. If there aren't water stops under the sink, turn off the main water supply valve for the house.

2. Unscrew the Allen set screw at the base of the handle that holds it in place, using the proper size Allen wrench. Remove the handle.

3. Lift off the round collar by hand.

4. Unscrew the retaining nut at the top of the cartridge. Pull out the cartridge, using slip-joint pliers.

5. Hold the base of the cartridge with one set of slip-joint pliers and pull the plunger with another set of slip-joint pliers. Pull until the two parts are completely separated.

6. Remove the old O-ring and replace it with the same size O-ring from the kit. Lubricate the two parts of the cartridge with plumber's grease. Reassemble the cartridge and install it into the faucet the same way it was removed. Replace the handle and turn on the water supply.