Hi,
When my upstairs toilet is filling, it is making a VERY, loud banging noise. Sounds like a jackhammer in the wall. At first it was happening on occasion, but now it happens every time it's flushed. It's not just one bang, it's repetitive and doesn't stop until the tank has refilled itself. My husband adjusted the flow to the toilet so it barely trickles in to temporarily alleviate the problem. Thought we would see if this was something we could fix ourselves before we call in a plumber.
Thanks!

It sounds like the problem is with the ball cock, the noise you hear is the washer vibrating against the seat as the tank fills.
The solution would be to S/O the water at the angle stop, remove the tank lid and remove the three screws on top of the ballcock pull the float ball and stem and washer assembly up and out, Pry the washer out with a flat screw driver and turn it over. With the ballcock still open, slightly turn on the water to flush the supply out. Check the linkage between the flapper and the flush lever. It should have ¼” to ½”of play when your tank is full.
(Loose washer at end of angle vale stem will also make the noise)


See the images below and confirm which type fill valve do you have, Thanks.

John

Thanks so much for your detailed answer, John! I will give it a shot when I get home and post my success or failure!

Please tell me which one is your fill valve from the images above, Thanks.

John

Going from memory (I am at work), I am pretty sure it's the one on the right. I know it has the big ball thingy.

Good then follow the instruction above in post #2 and see the image below, remove the screws and the washer check the washer that it is not torn if looks OK, flip it over and assemble, if this would not fix your problem then you have a loose washer inside the angle valve, come back and we will help you how to fix that problem, thanks.

John

Hi John, I just followed the instructions to check the washer. It looked OK and I flipped it and reassembled, but we still have the jack hammer in the wall. So I am ready to conquer the angle valve. Thanks for your help, Maria

Hi Maria,
Thanks for the update, now you have to close the main water S/O valve to the house, flush the toilet, remove the packing nut and the stem to get to the washer, see the image below, good luck.

John

Hi Maria,
I forgot to ask you when you removed the screws and the washer to flush the fill valve before you assemble it back, check the angle valve first see if the washer is loose or broken, if it is replace it.

If that will not fix your problem once again close the angle valve, remove the screws and the washer, hold your hand on top of the fill valve open the angle valve slowly for a few seconds to flush out any debris from the fill valve, check and let me know, Thanks.

John

SUCCESS! We ended up replacing the entire valve because "the helpful hardware man" said they didn't have just the washers. It was pretty simple and we have a quiet toilet once again. Your assistance was invaluable... what could have cost $100's only cost $7! THANK YOU!

Hi Maria,

Thanks for the update, it is our pleasure to help, please don’t hesitate to come back to this site if you have any plumbing questions, Thanks.

John

John, what if it happens when you flush any toilet in the house? We have two and it happens when either one is flushed. We have a one story house, so both are located on one floor. Is it possible both fill valves are bad? We hear the same banging when the washing machine is filling with water... is this also coming from the same toilet problem?