I have one of the stupid push button down to flush type cisterns. Not 2 halves but only one button. It is driving me nuts. It stops flushing. I take out (unscrew) the silver button part. Screw it back on again.It then works fine but it only lasts about a dozen or so flushes before it stops again. What is the secret to refitting this button to get it to function correctly?
I can't answer your question, but our push-button often keeps drawing the water after it's flushed - we just go back in and dib the button and it shuts the valve.
Sounds like it's one of those that acts directly on the syphon. Even these don't usually give this much trouble. I would suggest that the mechanism has distorted/cracked/moved. Unless you can see exactly what the cause is, You probably need a new syphon. The cable operated ones are better..........