your siphon diaphragm has a hole in it. buy a new one(or a whole new siphon as they are fairly cheap) replace according to the instructions. if you have a close coupled cistern( bolted straight onto the toilet) this can sometimes( nearly always) be a pain to get off. try to get hold of a fluidmaster type flush which can be repaired or replaced from inside the cistern without having to split them apart in the future.
kev, June 2004
