Toilet cistern problem

[euro67]

My toilet does not always flush.

The cistern fills fine and the handle moves fine.

However, when the handle is used the water starts to flush, gurgles for 1/2 second and stops.

Even pumping the handle does not make it work.

Anybody got any ideas, short of replacing the big plastic thing (syphen unit) in the middle of the cistern?

If I do need to replace the syphen, does anybody have an idiot proof set of instructions?

[Tweed]

My guess is that the syphon has split and needs replaced. The most difficult thing about replacing one is unscrewing the old screws/bolts that have rusted through time.

[madham]

Mine did this, inside the bit attached to the wire there is like a tube with a plastic like sheet and when you turn the handle the plastic goes upwards flat, that makes the water flush out at the top and it simply had a tear in the plstic, sounds complicated but simple to fix, so don't pay a plumber to sort it.

[BillyBB]

The plastic sheet is known as a diaphram, they are different shapes to look inside your cistern before shopping.