Prepare for New Cartridge Installation — Prepare and Install New Cartridge

Beginner3 hours

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How to Identify and Replace Your Delta Monitor Shower Cartridge (Old vs. New) · Step 5 of 7

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In this video

Before installing the new cartridge, inspect the inside of the brass valve body to ensure the old rubber gaskets did not get stuck inside. If they did, use a small pick to remove them. Wipe the inside clean with a towel. Apply a small amount of the included silicone grease to the two rubber gaskets and the large O-ring on the new cartridge. This helps create a good seal and makes future removal easier.

Goal: Prepare the new cartridge and valve body

Do not install the new cartridge if old gaskets are still inside the valve body, as this will cause a leak.

Used in this video

Towel — Cleaning the inside of the valve body.
Small Pick · optional — Removing old gaskets that may be stuck inside the valve body.

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FAQs

How do I confirm if I need the older gray RP19804 or the newer white RP46074 Delta cartridge before I start disassembly?

While some Delta handle styles can offer clues, the most reliable method is to remove the handle and trim plate to visually inspect your existing cartridge. Note its color (gray or white) and any distinguishing markings or numbers to ensure you purchase the correct replacement part.

The project lists several tools; which are absolutely essential for a successful cartridge replacement, and can I use basic alternatives?

You'll primarily need slip-joint pliers or Channel Locks for gripping the bonnet nut and a Phillips head or flat head screwdriver for the handle and trim screws. While specialized tools are listed, basic versions of these are often sufficient. Ensure your chosen pliers can provide a secure grip without damaging plastic components.

What should I do if I can't locate my main water shut-off valve, or if the water doesn't completely stop flowing after I turn it off?

First, check for an individual shut-off valve to your bathroom or shower, often found behind an access panel. If no such valve exists and the main shut-off is inaccessible or faulty, it's best to contact a professional plumber to avoid water damage and ensure a complete water stoppage before proceeding.

I've replaced the cartridge and reassembled everything, but the shower still drips, leaks, or has reduced flow. What could be the issue?

Double-check that the new cartridge is fully seated and properly oriented; the 'H' and 'C' markings usually align with the hot and cold lines. Ensure the bonnet nut is tightened securely, but not overtightened, and verify that all O-rings are in place and adequately lubricated with plumber's grease.

Transcript

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of the cartridge out. Now looking at the back of the new cartridge you'll see it has two rubber gasket. Now on the old one that I have there are no rubber gaskets but you definitely want to check the shower you have because when you're removing the old one make sure the old gasket is not stuck on the inside surface of the valve. If it is use a small pick and remove the old gasket. You don't want to double up the gasket when you install the new one because it'll cause a leak. You can get a towel and just wipe this and clean this. Now in this new cartridge there's a rubber o-ring and two gaskets here. Well I do supply some silicone grease on the surface of the old ring and the gasket. Now you don't have to put a lot. You just put a little bit. If you don't have it it's okay but this will help with removal in the future. Now go ahead and remove the towel. To install this new cartridge you'll notice

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