First, I 'll explain how it works and then I'll take photos. There is a rod that extends vertically from from top to bottom of the bucket and at the bottom there is a rubber flap or valve surrounded by a couple of washers affixed with a nut. This valve is pushed up by the water when the bucket hits and is filled.I don't know if I understand. So it has some type of check valve at the bottom? Does it drop all the way through the casing?
Can you take it out and shoot a video of it in use? Lol
When the bucket is filled the valve sort of
'floats" with a full load until you start pulling the rope to retrieve the bucket. Then the flap drops back on the 'fill hole" to retain the water. One the bucket is at the surface, (remember the rod?) you position the bucket over your 5 gallon bucket, pull the rod at the top and it discharges the water. Quite simple but effective.
On this particular bucket due to its age, the rubber flap had rotted out so I bought some more rubber and fabricated a new valve.
You can see in the photos the pull ring at the top and the bottom photo shows the rubber and a bracket that holds the bottom in place.
I hope this helps.