If you have to replace the cartridge inside of your Moen shower body then you will need to follow a few simple steps.The Moen Shower Body cartridge inside of the posi-temp, Moen plastic cartridge and also the brass cartridge can all be removed, replaced and possibly rebuilt depending on the condition and age of the cartridge that is in the shower body. You will also need some tools to remove the cartridge form the Moen shower body. You will need a Moen cartridge puller, a Flathead screw driver, a Philips head screwdriver, and possible a pair or vise grips if the cartridge is really stuck inside of the shower body.
Once you have all of your tools ready you will want to make sure that the water is off to the shower body. You can just shut the water off to your shower if you have isolation valves for that fixture, meaning you will have separate valves to shut the shower body. If you do not have isolation valves to shut the water off to the shower you are working on you probably will have to shut the water main to your home of business. You must have the water shut off in order to remove the moen shower body cartridge. You cannot change, replace or even rebuild the cartridge if the water is still on.
Once you have the water off you now will be able to start taking apart the shower body so you can replace the cartridge that is currently leaking, dripping or just completely needs to be replaced for whatever reason. Once again, before you get started you will want to double check to make sure that the hot and the cold water are completely off to the shower body you are working on. There are three kinds of cartridges that you can have inside of your Moen shower body. You can have a standard plastic or brass cartridge or you may have a Posi-temp style cartridge. Either way you will be removing the cartridge that you have the same way with the same tools.
How To Remove Moen Shower Body Valve Cartridge
The first thing you will want to do is to make sure that the water is off by opening the valve on your Moen shower body by turning the handle. If the water is off this will allow the hot and the cold excess water can come out of the shower body so when you are working and pull the cartridge out you will not get soaking wet.
Now that the water is off and the excess water has drained from the shower body you will want to remove the handle and the trim of the shower body. You can do this by removing the cap of the handle and then removing the set screw that is inside. Here is a picture of the handle and the set screw. You will also need to remove the two Philips head screws that hold the shower body valve trim onto the shower wall. Once you have removed the handle and the trim from the shower body you will be able to see the actual body of the shower valve as well as the stem you are about to remove. Here is a picture of the shower body valve with a cartridge inside of the body.
The next step is to remove the U shaped clip that holds the Moen shower cartridge into place when the valve body is under pressure or in simpler terms, when the shower is on. You can take a Flat head screw driver and pry the U shaped clip out of the shower body valve. Here is a picture of the clip that you will be removing. Please note, that you will need to replace and reinstall this clip when reassembling the shower body after you you swap and replace the cartridge.
Once the cartridge u clip has been removed from the shower body valve you can use a cartridge puller to remove the cartridge from the shower body valve. If you are having trouble removing the Moen cartridge from the shower body you can use a pair of vise grips to grab the brass shaft of the cartridge instead of using the shower body cartridge removal tool. But in most cases the puller will pull the cartridge right out for you. Here is a picture of the shower body cartridge removal tool. Once you have pulled the cartridge out of the shower body valve you will be able to clean and wipe out the inside of the shower body and then re insert your new replacement Moen cartridge. This is a picture of what the Moen Shower Body cartridge will look like after you remove it. If your cartridge is still in decent shape but just has some flaws you can use a rebuild kit and rebuild the Moen cartridge if you choose or you can just replace the whole entire cartridge at once. Here is a picture of what comes with the Moen shower body cartridge rebuild kit. It comes with new o-rings as well.
Re-inserting The New Cartridge
When re inserting the new Moen cartridge always make sure to lube the rubber on the cartridge so the new cartridge can have an easy operation and long lasting life.
The Cartridge Is Totally Stuck In The Shower Body Valve
If you have tried everything and you still cannot remove the cartridge from the shower body you may want to replace the entire shower body valve with a new one. But first you may want to try to clamp on a pair of vice grips and then using a claw hammer, try to ply the shower body from the valve gently. If the cartridge is still stuck, you may need to replace the showe body at this point or call a licensed plumber to try to remove the stem for you.
Where Can I Buy A New Moen Replacement Shower Body Cartridge?
You can buy a new replacement cartridge from many places including hardware stores, home centers, and of course local plumbing supply stores. You also can buy a new cartridge right online as well and often buying the replacement Moen cartridge online is less expensive.