HOW DO I: Replace a shower valve cartridge? | Features

There are times in life when you may experience a leaking shower valve and you wonder how you might be able to repair it.

Well, today’s article might shed a little light on that project.

If working with plumbing and water-related issues is too uncomfortable for you, I suggest you call your local plumber of choice and hire them to do so. If, however, you are a die-hard do-it-yourselfer, I know that advice will go in one ear and out the other.

There are many brands of shower valves in this world, and each brand has slightly different detailed measures of how to go about replacing their cartridge. On top of that, each brand itself has different models that may differ slightly, but the general principle is the same. The brand I am going to explain today is the Moen brand.

It is a very common shower valve that many of you have in your showers, so if you have one in need of repair and you have never done it before, you are in luck. If you have another brand that is a bit different, then maybe not so lucky.

The list of tools you will need are quite simple – a #2 Phillips screwdriver, a small flat-tipped screwdriver or other small sharp object to pry with, a 7/64 Allen wrench and a pair of pliers.

To start with, remove the handle. If it is the old acrylic ball handle, use your sharp-edged prying tool to remove the center screw cover to access the #2 Phillips screw that holds the acrylic ball to the cartridge stem.

If you have a single-handled lever, you will need to remove the small set screw located on the bottom of the handle’s bell housing using the Allen wrench. Once the set screw is loose, the handle will slide off the cartridge stem.

Most of the time you would remove the large escutcheon plate from against the shower wall surface, but if enough of the cartridge sleeve is extended beyond the escutcheon plate, you can leave it in place, saving you time in the process.

If the cartridge sleeve extends only a short way beyond the escutcheon plate, this means the wall surface is thick, such as when the walls are tiled with a mud bed and would require removal to access the keeper pin that you will see shortly.

Either way, remove the cartridge sleeve by pulling it forward and it will expose the stem and cartridge. You will notice a keeper pin or clip inserted down into the body of the cartridge.

This clip has two legs spaced about ¾ of an inch apart connected along the top of the cartridge with either a hole or slot in which you can use a small flat tipped screwdriver or pair of pliers to pull upward and out of the cartridge body. Before you pull it upward, you can see the legs of the clip in front of the cartridge body holding it in place.

One word of caution here. Don’t do what I did about 17 years ago. I was in quite a hurry and pulled the clip out before thinking about the water pressure behind it. Yes, that’s right. You might say, I had no problem getting the cartridge out as it flew out followed by a mighty gushing torrent of water. It was then that I remembered I had forgotten to shut off the water.

That is a predicament you don’t want to find yourself in because you must think as quickly as any computer on the market, all the while water is gushing out of the wall.

Guess what you think about? You think about how quickly you can get your hand in front of the water to plug it up. Refrain from this thought. It may be OK if you need to plug a leaking dyke, but, inside a bathroom, the moment you try to plug it, you realize how foolish that thought was as you see water begin to go in all directions inside your bathroom with the same effect as a water hose that you put your thumb over.

The best advice is to let it flow while you run to the nearest shut-off valve or water meter to stop the embarrassment and any further water damage.

After removing the old cartridge and inserting the new one, reinstall the clip until it snaps in place.

The cartridge goes in in one direction only. The cartridge should have a rectangular plate on the front with an H on the left and a C on the right. This stands for Hot and Cold. The H should be on the left side, while the C is on the right, and the cartridge will be in correctly.

Once this is complete, turn on the water and check for leaks and reassemble the cartridge sleeve, escutcheon plate, if it had to come off and the handle and you’re done.

Always turn off the water before you begin this repair, and you will do just fine. However, if this story makes you nervous, you can always call your nearest plumber.

JD Norris is the owner/operator of DreamMaker Bath & Kitchen and a certified S.C. Master Builder, certified "Aging in Place" Specialist and certified Green Professional. If you have any projects that you would like discussed in an upcoming article, email jdn.dm@comcast.net.