Repairing a leaking tub diverter spout is a relatively easy task that most people can do themselves. It is normal for a small amount of water to come out of the spout when the shower is being used but when the amount is large enough and the shower water volume suffers the spout should be replaced.
The small amount of water bypassing the diverter and coming out of the spout is by design to allow the water in the shower riser to leak down and allow the diverter to reset so the next shower user does not receive a cold blast out of the showerhead when they turn on the water. Instead water will come out of the tub spout allowing them to set the water temperature. Most diverter tub spouts are inexpensively constructed and there is no repairs that can be performed on them, so replacing the spout is required. Most diverter spouts are of die cast construction and the metal may corrode allowing excessive leakage out of the spout while showering or, in some cases at the connection to the pipe stub coming out of the wall will start to leak. The connection to the pipe stub leaking in many cases is noticeable by water coming out of a drain hole on the bottom side of the tub spout where it meets the wall. In some cases if the drain hole has been caulked over or, the leakage is a higher flow than the drain hole can handle water will pour back inside the wall when the shower is running causing leaks to appear below the tub often damaging ceilings on the levels of the home below the tub.
There are three basic designs of diverter spouts for bathtubs with showers, and the tools required will vary depending on which type you have. The most common is probably a diverter spout that screws on to a pipe nipple or, pipe stub with a threaded adapter sweated onto the end of the spout. Rapidly gaining popularity because of the ease of installation and the expanding Do It Yourself marketing by many tub/shower mixer manufacturers is the slip on diverter spout, which uses a connection that slides over a copper pipe stub sealing with an o-ring and locking in place with a set screw onto the copper pipe stub. The last one is the Delta tub/shower diverter spout that has an adapter that either threads onto a pipe nipple or, is sweated onto a copper pipe stub coming out of the wall. The Delta tub/shower diverter spout is easily recognized by its unique appearance and the pull down diverter operation instead of lifting a knob.
Recognizing which tub/shower diverter spout is key to avoiding damage to your pipe coming out of the wall and making the job easier. If you attempt to turn a slip on tub spout that locks onto a copper pipe stub with a set screw you can very quickly turn an easy job into one that requires using a plumbers torch. In some cases if the original installer turned the spout after locking the set screw the set screw will no longer line up with the hole. If the spout is not a Delta pull down type spout in most cases it will have a die cast shell around the attachment. I usually cover the tub drain with a rag then crush the die cast shell with a pair of channel lock pliers exposing the attaching mechanism. If the spout threads on then I can use a wrench to hold back on the stub out of the wall while unthreading the spout or, easily see and remove the set screw holding on a slip on spout.
To replace a screw on diverter you will need a new spout matching the dimensions of the old spout for attachment or, be ready to adjust the stub out length possibly involving sweating copper pipe with a plumbers torch or, cutting the adapter off and using a slip on spout. To replace the spout with a matching spout you will need the spout, Teflon tape, Teflon paste, a measuring tape, channel lock pliers, a pipe wrench to hold back on the pipe nipple (if one is used coming out of the wall), an adjustable wrench to hold back on the threaded adapter (if copper pipe comes out of the wall), and something to put into the end of the spout to aid you in turning the spout tight. Unscrew the old spout off the stub and threaded adapter then wrap Teflon tape over the threads, apply Teflon paste over the tape and thread the new spout tightly into place ending with the spout facing in the down position and level. I have strong hands and can get it sufficiently tight but many people have to use something inserted into the spout to assist turning. Be careful not to damage the spout. Test for proper operation and leaks and the job is done. In most cases caulk is not required, and if you caulk the spout, you should only caulk the upper half of the spout where it meets the wall, never caulk the drain at the bottom closed.
To replace a slip on diverter spout you will need the new spout, plumber’s grease, possibly plumber’s cloth or, a file if there are burrs on the stub, and an allen wrench. Remove the slip on spout by loosening the set screw with the allen wrench. Slid the spout off the stub using a twisting, turning motion while pulling it off. Inspect the stub making sure there are no sharp burrs that will damage the sealing o-ring on the new slip on spout. If there are any burrs remove them with the plumber’s cloth or file before attempting to slip on the new spout. Apply a light coating of plumber’s grease on the stub to where the o-ring will sit when installed this will help prevent damage to the o-ring. Slide the new spout into position tightly against the wall and level with the spout facing down then use the allen wrench to tighten the set screw, taking care not to over tighter the screw into the copper tube. Test for proper operation and leaks and the job is done. In most cases caulk is not required, and if you caulk the spout, you should only caulk the upper half of the spout where it meets the wall, never caulk the drain at the bottom closed.
To replace a Delta pull down spout you need to pick up the new spout either the Delta # RP17453 plastic spout, or, # RP17454 metallic spout. Examine the new spout and how it attaches will be self-evident. Remove the old spout from the adapter on the nipple or stub out unthreading it from the adapter then pull off the old spout. Transfer the o-ring on the new spout’s adapter, to the old adapter mounted on the stub out, apply a light coating of plumbers grease to the o-ring. Then slide the new Delta pull down diverter spout onto the adapter and tighten it against the wall with the spout facing down and level locking it in place. Test for proper operation and leaks and the job is done. In most cases caulk is not required, and if you caulk the spout, you should only caulk the upper half of the spout where it meets the wall, never caulk the drain at the bottom closed.