How to Repair Shower Valves

Clogs or worn-out O-ring seals can interrupt the flow of water through a tub and shower valve. Repairing a single-handle cartridge-style tub and shower valve is not the easiest plumbing problem for the DIYer to fix, but it should not take more than an hour, even if this is your first attempt at plumbing repair.

Mineral deposits and worn sealings are the most common cause of tub and shower valve problems.
  1. Use the end of a small flathead screwdriver to remove the cap of the tub and shower valve. Use a Phillips screwdriver if the screw is not made for a flathead driver. Removal of the cap should reveal a screw that you should also remove.

  2. Remove the handle after removing the screw and set them aside in a safe place. Look for a setscrew. If you can’t find it immediately, look for a cap that may be covering the setscrew. Loosen the set screw with either a screwdriver or Allen wrench, depending on the type of setscrew.

  3. Remove the plate, what professionals call the escutcheon. Different models require different procedures of removal. Some models may even require chipping away the ceramic tile to remove the escutcheon or removing parts between the handle and the body of the valve. As you remove each part of the faucet, set it aside in the order in which you removed it to prevent any confusion during reassembly, when you replace the parts in opposite order from removal.

  4. Check to see if if the valve has stop-check parts. This part looks like a large plug with slotted heads in T-fittings that are on both the hot and cold lines to the valve. If you have stop-check valves, turn them off by twisting them clockwise. If there are no stop-check valves, you can simply shut off the hot and cold water lines.

  5. Locate the retainer clip shaped like the letter "U." If you cannot find this, remove the nut locking the cartridge to the valve with a channel-type wrench. Use locking pliers to grab hold of the cartridge and lift straight up until the cartridge has been removed.

  6. Flush the lines by turning on the water. Use a toothbrush to clean out debris that could be causing clogging. Inspect the O-ring for damage and replace it if necessary. Use the toothbrush to clean the cartridge, and then reassemble the tub and shower valve in reverse order of how you took it apart.