Diaphram membrane has split needs new membrane but if old type that can only be repaired removing it from cistern then you might just as well buy a new syphone.
Start by turning off the water to the cistern. Bale out the water in the cistern. Depending on type. Low levels are easy remove the flush tube from both pan rear and cistern then undo the large plastic nut under the cistern that holds the syphone in place. Remove the syphon and fit the new one. The hard one is the close coupled one the cistern bolted to toilet and fixed to the wall again turn off the water remove the water feed pipe unscrew the wall fixings unbolt the cistern and remove the syphone as above. New syphon and new doughnut seal set includes the plate and bolts. When done if you had a job getting bolts off then vaselene [petrolium jelly helps to stop bolts going rusty.
Bob, May 2009
