I am trying to repair a 90 year-old toilet whose wall-mounted tank connects to the bowl without bolts. I can't find any apparent brand markings, although I did find the numbers "1 603H", 28, and 1916 on the tank lid. No ****** searches have turned up any results on what kind of toilet this is or what type of parts to use.

There's a pipe running from the bottom of the tank (via the flush mechanism) to the top of the bowl. As far as I can tell, the system relies on pressure and washers to ensure a tight seal, but the standard rubber washers I bought at home depot don't seem to be doing the trick. I've tried plumbers epoxy but it still leaks.

I've been unable to repair the flush mechanism without it leaking, and as a result am unable to even begin to figure out how to reconnect to the tank. I'd like to replace the whole flush mechanism, and pipe/connection to the bowl, but I don't know what parts to use, or even where to look.

The attached picture shows the pipe and connectors running from the tank to the bowl. The black is the dried out old washer that had fit in the bowl. Again - no bolts...

I'm feeling pretty good about having successfully reinstalled the toilet bowl and remounted the tank on the wall, so I'd love to finish the job. Anyone have any recommendations or ideas?