Hesitant Handyman Repairs - How to change a Delta Monitor shower cartridge...
We’ve owned our house for nearly three years, and shortly after moving in, our master shower developed a slow drip. At first it was barely noticeable, but in recent weeks it got worse. Like, we had to shut the bathroom door when we went to bed because it would keep us awake worse.
The culprit was the shower cartridge–the home’s just over a decade old, and sometimes these things wear out and need to be replaced. I’d never done it before, but the task seemed simple enough. And really, it wasn’t that the task itself was hard–if everything went without a hitch, it would’ve been a 20-30 minute job. I encountered a few challenges that, while solvable, made it take a little bit longer, and resulted in me replacing the trim as well (the good news is–this gave me the opportunity to match the shower head we recently purchased, since it was a stainless steel finish and our old trim was chrome).
Here’s how I did it!
Software
Hardware
Turn off the water to the fixture
If you followed along on my replacement of the seats and springs in my bathroom faucet, you know that I had a handy shutoff at the fixture that allowed me to turn off the water in the same room as the faucet I was working on. Our shower, on the other hand, lacks any shutoff at the fixture, so I had to turn off the water to the whole house to work on it.
If you have a really good home builder, they likely were super thoughtful and put an emergency shutoff somewhere easily accessible, like near your water heater, in the garage, or in the basement. The person who built my home wasn’t that thoughtful.
If you don’t have an emergency shutoff in the house, your next location will be the home-side shutoff at the water meter, which is typically at the curb in front of your house. For most people, this isn’t a huge deal, but I live on a flag lot. This means, in the event that there ever IS a water emergency, I get to sprint a 100 yard dash out my front door, down the driveway to the water meter. If you’re not sure where your meter and emergency shutoff is, your local utility company can probably give you the info on this. (Mine wasn’t clearly marked, so I had to call the city out to give me directions on where it was). It should be obvious, but you don’t want to do any work on anything plumbing related without turning the water off first. Once I shut off the water, I opened the faucet to release any pressure built up in the system.
Remove the handle trim
After I got the water shut off, I ran into my first problem–the set screw in the handle was stuck. I worked at it with a hex key, but it was stuck badly enough that I managed to strip out the head. After consulting with a contractor friend, I wound up snagging a set of left hand cobalt drill bits. The theory was, because the left hand drill bits are corkscrewed the opposite direction of a standard drill bit, it should go in and bite on the set screw, then provide sufficient torque to break it free and come out.
It never caught the set screw, but eventually I mangled it enough that I was able to pull the handle free. I went into the process expecting to have to replace the handle, so the wanton destruction I’d wreaked upon the chrome trim kit wasn’t really a setback, but if you don’t have a spare trim kit sitting around, you might find another method of removing a stuck set screw.
Remove the bonnet nut
The bonnet nut is what holds the cartridge in the faucet body. It’s a nondescript brass ring hidden underneath the decorative sleeve that covers the cartridge. In my case, it was also stuck, which resulted in me trying a plethora of things to try to unstick it. From sheer brute force to water pump pliers, from heat from my wife’s hairdryer to more brute force, I tried everything I could think of to loosen it, with no luck.
At this point I delved into the great community knowledge of the internet, and found this video from a YouTuber named Jimmy Moonshine who addressed my problem in a method that struck me as both procedurally questionable and just crazy enough to work. To sum it up, he advocated using a Dremel or a file to cut a shallow groove into the bonnet nut, setting a screwdriver into the groove, and then tapping on the screwdriver with a mallet to knock it loose. I took out a file and carved in a groove and, to my utter shock, it actually worked. A couple quick hits of the mallet and it spun free.
Remove the old cartridge
The old cartridge, having been in the faucet for ten years, was also stuck pretty good, but thankfully nowhere near as challenging as the first two problems I encountered. Basically, I grabbed it with both hands and tugged and jiggled it until it finally came loose.
Install replacement cartridge
The prep is pretty simple–I applied some silicone grease to the O-rings on the cartridge to allow a better seal when everything was put back together. One key thing to be aware of is which direction your shower handle turns to hot–the Delta cartridges are pretty obviously marked with which side is the “hot” side, so you’ll want to make sure that side is pointed towards the “hot” direction of the handle.
The cartridge will be a pretty snug fit–there should also be a small V in the housing that lines up with a V on the cartridge to make sure the cartridge is in correctly. Also, make sure you check your heat limited to ensure you don’t scald yourself. In my case, the old cartridge was old enough that this wasn’t integrated into the cartridge, so it fell off and I didn’t know where it was set before, so I had to guess.
Install the new handle (or reinstall the old one)
You’re basically reversing your disassembly process here. Add the sleeve, escutcheon plate, and handle according to your instructions if installing a new one, or just undo what you did if you’re still using your old one.
Turn the water back on and test the new cartridge
Because of the arduous trek I had to make to get to the water shutoff valve, I had my wife get ready for me on speed dial in case she heard or saw water spewing from anywhere it wasn’t supposed to be. Thankfully, it didn’t, so I went back to the bathroom and tested the new cartridge. The water flowed, the hot water was hot, the cold water was cold, and–most importantly–when it was turned off, there was no longer a persistent drip.
Disclaimer: Most DIY projects involve risk of some sort. Your tools, materials, and skills will vary, as will the conditions at your project site. The Hesitant Handyman has made every effort to be complete and accurate in the instructions provided on this content. The Hesitant Handyman will not assume any responsibility or liability for damages or losses sustained or incurred in the course of your project or in the use of the item you create. Always follow the manufacturer’s operating instructions in the use of tools, check and follow your local building codes, and observe all commonly accepted safety precautions.
