How to Repair Leaky Moen Shower Faucets
- 1). Shut off the water to the shower before you begin. If you don't have a dedicated valve on the supply lines for the shower, turn off the main shut-off valve for the house.
- 2). Pry off the cap from a plastic shower handle with a slot screwdriver if you can't see the screw. Once the cap is off, you'll be able to unscrew the handle with a Phillips screwdriver. If the handle is a metal lever, look for a set screw underneath it and unscrew this with an Allen wrench to remove it.
- 3). Lift the plastic limiter off of the valve stem if your faucet has a temperature limit function. Pull out the stop tube, which is the metal sleeve around the outside of the valve stem. Use needle-nose pliers if you can't get it off by hand.
- 4). Unscrew the nut holding the cartridge in the valve stem with slip-lock pliers, grasp the valve stem with the pliers and pull out the cartridge. In some models, the cartridge is held in place by a pin or clip. If this is the case, pull out the pin with needle-nose pliers and then pull out the cartridge.
- 5). Replace the seals in the valve inlets. Pry them out with a slot screwdriver and insert replacements, pushing them with the tip of the screwdriver to seat them. Replace the O-rings around the cartridge if they are worn. Work them off with the screwdriver, then slide new ones in place, using a little petroleum jelly for lubrication.
- 6). Look carefully at the cartridge. If it is plastic, it could be cracked. If so, take it to a plumbing supply store to use as a reference for buying a replacement. If the cartridge is covered with mineral deposits, you may be able to scrape most of them off with the screwdriver. If they are excessive, soak the cartridge overnight in white vinegar to dissolve them. In the same way, scrape off deposits inside the valve seat. Mineral deposits can prevent the cartridge from making a watertight seal.
- 7). Slide the cartridge back into the valve until it is fully seated, then slide the pin back in place or screw on the retaining nut. Slide the stop tube back into position, and replace the plastic limiter. Replace the handle, screw it on, and snap on the cap, if there is one. Turn on the water and test the faucet.
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