Just discovered that the flush pipe on a concealed cistern is leaking. Fortunately no serious damage has occurred. This is a system installed
40 years ago and has not been touched meantime. The leak is at the flush pipe to cistern join. The flush pipe enters at an angle. I propose to replace the flush pipe with an L shaped one which will align the join. However I don't know how the connections at each end are constructed. Can someone explain? The cistern end has a plastic nut but I cannot see how that is sealed and cannot locate a replacement part in any of the plumbing catalogues - well screwfix & toolstation actually. Flush pipes seem to be 1 1/2" diam. How is this join sealed? The WC end seems to use some form of "gooey tape". What is this and how is it used.
Your collective advice is much appreciated. Frank
PS My earlier "urinal flush mechanism" problems [nothing to do with an aging prostate!] are well on the way to being solved thanks to your replies. I just have to remove a stubborn 22mm olive on the existing pipework!