we have a push button toilet which is leaking from the back. My husband took the cisten off the pan and we sealed all the screw holes with sealent- which are now fine.
Having left it half an hour we found we still had a leak. (bear with me while I try to explain!)
At the back of the toilet pan there is a shallow area where the cisten sits: our cisten doesn't sit snug on the pan, leaving a gap around the bottom- if the toilet hasn't been flushed for a while there seems to be a build up of water in this shallow area which "overflows" trickling down the pan. We used to have a sealent along there but obviously the water found a way out still. Should we attempt to seal this area completely round the bottom of the cisten??
Two reasons the main is the nut securing the syphon to the cistern has either no seal washer or is not tight enough to cause the seal.
Or it could be the close coupled bolts are not tight enough to form the seal and this may cause some of the flushed water to escape. Try tighten the securing bolts.
The worse senario is having to remove the cistern and replace that doughnut seal. [some nicknamed them doughnuts because of their shape] obtainable in most plumbing stores.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix toilets.