How to Replace a Toilet Fill Valve – disconnect the PVC water supply hose and remove the old ballcock float ball valve.
This project is continued from How to Replace a Toilet Fill Valve – Part 1.
Disconnect the Toilet Water Supply Hose
Unscrew the coupling nut that attaches the water supply hose to the toilet fill valve. This is located under the tank on the left side of the toilet. The nut usually has large “wings” to unscrew by hand. Use a large adjustable wrench if the plastic nut is stuck.
Take care to shut off the water supply valve (valve at the bottom of the photo) before unscrewing the nut or you’ll have water gushing out and flood the bathroom!

The water supply hose nut is unscrewed from the fill valve threads. The supply hose is now loose – several ounces of water will run out of the fill valve. Use a towel to catch the water.

The toilet fill valve lock nut holds the valve body against the toilet tank. Use a 10-inch adjustable wrench (or channel locks will do in a pinch) to unscrew the nut:

The fill valve is loose inside the tank when the lock nut is removed:

Toilet Water Shutoff Valve: Disconnect the Supply Hose
If you are not replacing the water supply hose, skip the next two steps.
Because I’m replacing the toilet connector PVC plastic hose with a reinforced Brasscraft hose, the old plastic supply hose is removed and discarded. Unscrew the compression nut with the adjustable wrench. If the nut is unusually tight, place a second wrench on the valve body to avoid torquing the copper water pipe:

Here’s the old PVC supply hose (a.k.a. toilet connector). While I’ve not had a PVC supply hose fail on me and cause flooding, this $2 plastic hose is simple to replace with a $6 reinforced Brasscraft toilet connector hose.

Remove the Toilet Ballcock Fill Valve
After unscrewing the lock nut, the old ballcock fill valve simply lifts out of the tank:

The toilet tank is ready for the new fill valve and flapper. Now’s a good time to wipe down the inside of tank to remove any remaining sediment and iron stains that couldn’t be reached previously:

View of the water supply shutoff valve and bottom of toilet tank. The reinforced Brasscraft toilet connector hose will be installed here:

This project is continued in How to Replace a Toilet Fill Valve – Part 3.
Thanks for reading,
Bob Jackson