Fluidmaster Fix It Zone
New Toilet Fill Valve Won't Turn Off & Can’t Get Top Off
* Removing top cap of newer 400 Series fill valve
For fill valves with black plastic adjustment rod
If you are attempting this procedure while the valve is already installed in the tank, then it is necessary to first turn off the water and flush out the tank.
With your right hand, reach under the float cup and push it up. Keep right hand under the float by grabbing the valve shaft and holding it tight. Do not let float cup drop.
With your left hand, grab the cap while placing your thumb on the side of the black lever arm (see picture below), and twist both the cap and the lever arm counterclockwise 1/8th of a turn. You may need to press down on the cap while making a quick twist. Once the cap assembly unlocks, lift it off.
The cap assembly includes the black cap, black lever arm, and the plastic housing that holds the seal.
The bottom hand is lifting up on the float cup, which raises the black arm at the top cap. The top hand is gripping the cap while the thumb is pressing on the raised lever arm and turning counter clockwise.