The shower/tub (single) lever kept coming off so I bought a new trim kit. I took off the existing and then realized the new one does not fit this cartridge stem. I put the old back together so I could at least use it with pliers and now the cartridge doesn't seem to work. When the supply is on the water just pours out the faucet and it does not control the temperature. Not sure what the issue is? There is a middle hole in the valve which looks to have something blue (like a rubber band) behind it and I don't know what thats about. And I've tried to find another similar cartridge and not been able to find one. Thanks for any help













To top it off I believe the original issue was just the set screw was loose and I didn't need to replace anything...



Edited 2 times.

You need to pull the blue rubber piece out, and place it in the grooves on the back of the cartridge.

Kudos to you, that was indeed a washer for the cartridge. I was afraid to pull that out not knowing what the middle hole is for (still wondering). Unfortunately nothing has changed as far as the water, it still flows unrestricted.

there also appears to be a piece of broken plastic in the picture

STOP YOUR WORK NOW

while the valve body is still salvageable

unit needs to be 'power flushed' using full line pressure BEFORE a new cartridge is installed

CALL A PLUMBER

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638