Step 4 · Extract the Old Cartridge

This is the step most people slow down on. Take it one move at a time — there’s no rush, and you can rewind the clip as many times as you need.

This step varies by brand. Before removing, note the orientation of the old cartridge. For a Moen Posi-Temp valve, you will see a small, U-shaped retaining clip at the top of the valve body. Use needle-nose pliers or a flathead screwdriver to pull this clip straight up and out. For a Delta Monitor valve, there is no clip. Instead, you'll see a large brass or plastic bonnet nut threaded over the cartridge. Use channel-lock pliers to unscrew this nut counter-clockwise. Wrap a rag around the nut to prevent scratching the finish. Once the retaining clip or bonnet nut is removed, the cartridge can be extracted. It may pull out easily, but if it is stuck, use pliers to grip the stem and twist back and forth while pulling. If it's very stuck, use a dedicated cartridge puller tool as instructed by the tool's manufacturer.