This just started leaking last week, each night the bowl is filled with clean water. I tried to tighten the 2 metal screws however that did not help. I am unable to see if there is a crack, but I think it may be that the rubber piece making a tight fit is old and worn out. What should I do?
I really couldn't tell where it is leaking from the photo, but if it is at that neoprene rubber coupling (aka a Fernco coupling) and tightening the ss clamps doesn't work, just replace it.
I would definitely remove the "Fernco" type coupling, clean the surfaces it seals against, and place a new coupling on. There should be a gap, not very much between the two pipes the "Fernco" is on and the coupling can be worked through this gap IF you cannot move the piping to gain more room. The piping needs to be in good alignment for the coupling to work properly. David