I just finished replacing the Moen cartridge (part # 1200) in my shower. This was my first attempt at a plumbing repair!
I had no difficulty, except for a bit of trouble dislodging the old cartridge (used a cartridge puller!)
The problem: The new cartridge turns on easily, and rotates very smoothly to adjust the temperature, but when I turn the water off the knob slides right back out about 1/4 inch, just enough to let the water drip. It acts like the water pressure is forcing the faucet to turn itself back on.
I can get the knob to stay in if I hold it in a few seconds, or if I turn it side-to-side a few times while in the off position, but if I just turn it off normally it just creeps back out again.
I can feel a slight resistance as I slide the knob in to turn it off, but it otherwise works smoothly.
Any idea what would cause this?
Thanks for any advice!