Repairing Tub and Shower Controls
Tub and shower controls work much the same way as sink faucets, so repairing them involves many of the same operations, except you are working horizontally rather than vertically. Also tub and shower controls are a bit more complicated because in addition to mixing hot and cold water, they must divert water either to the tub spout or to the showerhead.
Sometimes the parts are hard to get at. You may have to chip away at tiles in order to get your tools to the shower control parts. If a shower control body is damaged and needs to be replaced, look at the other side of the wall to see if you have an access panel. If so you may be able to work from behind and minimize damage to your shower wall. Usually replacing a shower control body means tearing up a shower wall and retiling.
Note: Be sure to shut off the supply stop valves, built-in shutoff valves, or the main water valve before making these repairs.
Two-handle control - The handles on these usually contain stems with washers. Each washer presses against a seat in order to shut the water off. To stop a drip, shut off the water, and remove the stem—you may have to use a special stem wrench or a deep socket, or chip away at the tiles to get at the packing nut. Replace the washer and the seat, if necessary, just as you would on a sink faucet. If the diverter valve on the spout is not working properly, replace the spout.
Three-handle control - This type is much like a two-handle control but it has a central handle that controls a diverter valve. The valve directs water either up or down—out the showerhead or out the spout. If the diverter valve sticks or if it does not completely divert water to either the showerhead or to the spout, shut off the water and remove the valve just as you would a regular stem. Take it apart, clean it, and replace any washers or O-rings. Or, replace the whole stem with a new one.
One-handle ball control - This type has seals and springs like ball-type sink faucets. As the handle is raised, the ball rotates in such a way that its openings begin to align with the supply line ports, allowing water to pass through the ball and out the spout. Impeded flow is usually the result of clogged orifices or worn seals. Shut the water off and remove the ball—a few ball controls have setscrews that you may have to remove to do this. Clean out the orifices, replace any worn rubber parts, and lubricate the new seals with heatproof grease. While you have the faucet apart, check the ball for wear and corrosion; if you find either, replace the ball.
One-handle cartridge control - There are other configurations of one-handled cartridge controls besides the one shown here, so you may have to search out the location of your parts, such as the retaining clip. Parts are usually made of plastic; be careful not to crack them. To repair a leak or limited flow, remove the handle, unscrew the retainer nut, and pull out the cartridge. Clean away any deposits and replace worn rubber or plastic parts. Lubricate all rubber parts with heatproof grease. Or simply replace the cartridge itself. When you remove the cartridge, be sure to note its original position and insert the new one the same way. If you don’t, your hot and cold water will be reversed.