Insert for thermostatic bath mixer tap cartridge head

My mixer tap was working hard because inside the cartridge head filled up with soak and limescale. About the forced use from the cap broken down all fastening pins. I could not glue it strong enough and some of parts just went down in to the drain, so I decided to designing an inlet and glue that in to the original cap.
First of course I cleaned the soak and dirt from inside and also used a little silicone grease between the plastic ring and the chrome surface, so after was easy to open-close