Hello, A leak has developed beneath my toilet cistern. Years ago, my father installed one of those in-line stop-taps on the pip supplying the cistern. If I turn the tap off, the leak stops, with just a slight weep until it ceases altogether. If I open the tap, the leak starts again.
The washer beneath the cistern is dry. There is no leak, with the stop-tap turned off and the cistern filled from a jug. The leak appears to be from the thread joint between the float valve and the stop-tap.
Coincidentally, it seemed to start when the ball was adjusted to stop the cistern overfilling slightly, and running through the overflow.
Is there anything I can do to stop the leak? PTFE tape? Is there any reason why it should start leaking after all these years?
Thanks, John