How To Remove Broken Shower Arm Thread

A broken shower arm thread can be a frustrating plumbing problem, but it is one that can be fixed with a little time and effort.

Turn off the water supply. This is usually done by turning off the main water valve for your home. If you don't know where this valve is located, consult your home's manual.
Remove the shower head. Most shower heads are attached to the shower arm with a simple twist-on connection. Simply unscrew the shower head by hand.
Loosen the broken shower arm. If the shower arm is still attached to the pipe coming out of the wall, use an adjustable wrench to loosen it. Turn the wrench counterclockwise to loosen the shower arm.
If the shower arm is stuck, try using a pipe wrench. A pipe wrench is a more powerful tool than an adjustable wrench, and it can be used to break loose even the most stubborn shower arms.
If the shower arm is still stuck, try applying some penetrating oil to the threads. Penetrating oil can help to loosen the threads and make it easier to remove the shower arm.
Once the shower arm is loose, remove it completely. Be careful not to damage the pipe coming out of the wall.
Wrap the threads of the new shower arm with Teflon tape. Teflon tape helps to create a watertight seal between the shower arm and the pipe.
Screw the new shower arm into the pipe. Turn the shower arm clockwise to tighten it.
Reattach the shower head.
Turn on the water supply. Check for leaks, and tighten the shower arm or shower head as necessary.

If you are having trouble removing the broken shower arm, you can try using a pair of pliers to grip the shower arm and turn it.
If you damage the pipe coming out of the wall while removing the shower arm, you will need to call a plumber to repair it.
It is a good idea to replace the shower arm washer when you replace the shower arm.