There are several types of faucets, each repaired in its own way. Before working on any faucet, shut off the water under the sink or basin and open the faucet to drain trapped water. Protect finished surfaces of fittings by covering the jaws of your wrench or pliers with electrician’s tape. Take any part you are replacing to the plumbing supply store and get an exact duplicate. When reassembling a faucet, coat all parts with heatproof, waterproof grease to provide a good seal, assure smooth movement, and facilitate later disassembly.
A stem faucet consists of a threaded stem assembly that turns the flow of water on or off, a seat washer that keeps water from leaking out the spout, and a packing nut and sealant that prevents leaks at the top of the stem. To disassemble a stem faucet, remove the handle, unscrew the packing nut or stem nut, and lift out the stem.
To fix a leak at the spout, remove the screw holding the washer and replace the washer. If your stem assembly has a diaphragm shaped like a top hat instead of a washer, pull off the worn diaphragm and snap on a new one.
If changing the washer doesn’t stop the leak, you may need to replace or resurface the valve seat. Examine it with a flashlight to see if it looks pitted and worn. Most newer valve seats can be removed with a seat wrench. Simply insert the wrench, turn it counterclockwise, and lift out the seat. Lubricate the outside of a new seat with pipe joint compound, push the seat firmly onto the seat wrench, and screw it into place.
If the seat can’t be removed, smooth the rough surface with a seat dressing tool fitted with a cutter the exact size of the seat. Screw the tool into the faucet so that the cutter is flush against the valve seat and the guide fits snugly inside the valve. Turn the handle of the tool until it moves smoothly. Remove the tool and rinse away the grindings.
Water seeping out around a faucet is usually the fault of the packing. Try gently tightening the packing nut. If the leak persists, replace whatever was used to seal the faucet stem: packing washer, O-ring, or self-forming packing. To replace self-forming packing, remove the old packing and wind enough new packing onto the stem to fill the packing nut, then add half again as much; the nut will compact it.
The interior mechanism of single-lever faucets differs from model to model. When repair is needed, a kit of replacement parts or a whole new cartridge must be purchased to fit the specific faucet. Detailed disassembly instructions are included in the kits. Remember to keep the drain closed and lay out the parts in the order you removed them.
Getting at the innards of the faucet may be your biggest repair challenge. As single-lever faucets become more streamlined, their screws are more carefully hidden-tucked under the lever or covered by decorative plates or buttons. When you find the screw, you may need a small Allen wrench to get it out; this usually comes with the kit. Shower and bathtub faucets To repair a wall-mounted shower or bathtub stem faucet you may need a plumber’s socket wrench to get the stem out of the wall. Chip away plaster, if need be, and insert the socket wrench into the wall. Repair as you would an equivalent sink or basin faucet. Repair a single-lever shower or tub faucet by replacing the cartridge.