I get a loud bang when I flush and the water drains, but then stops and doesn't fill back up. The bang is coming from the incoming water line. I had a plumber come out and he said to just disconnect the incoming line, let the air bleed out. It started as a once a day bang, but now it's every time you flush. I don't feel like bleeding out the line every time. How do you fix this? What could be the problem? To answer a few questions, yes the water is turned on. I have a private well system. There is a water hammer check valve on my holding tank. The bang is isolated to the line, but the bang is so loud you can hear it from outside the house!

Is the stop open all the way? Check to see if the washer in the stop is loose.is the fill valve old?

Yes the entire unit is old, but has been in working fine up until about two weeks ago. I thought a toilet either works or doesn't... there is no "going bad" on a toilet. I'll check the stop, I've got a good idea what your talking about, I'm just a dumb electrician not a plumber!

I get a loud bang when I flush and the water drains, but then stops and doesn't fill back up. The bang is coming from the incoming water line. I had a plumber come out and he said to just disconnect the incoming line, let the air bleed out. It started as a once a day bang, but now it's every time you flush. I don't feel like bleeding out the line every time. How do you fix this? what could be the problem? To answer a few questions, yes the water is turned on. I have a private well system. There is a water hammer check valve on my holding tank. The bang is isolated to the line, but the bang is so loud you can hear it from outside the house!
Air in the line has nothing to do with the water hammer. See my website for toilet water hammer info. You'll find the link at the bottom of Steam Water Hammer Forensic Investigation and Chilled Water Troubleshooting by Kirsner Consulting Engineering (http://www.kirsner.org).

I love the fluidmaster 400 toilet fill valve. It is about 8 bucks. You may want a stainless flex supply also. Read the instructions to adjust it before you install it.