How do I replace the flap valve in a close-coupled cistern

So we have the top of he cistern off, the handle removed, and we've undone the two bolts that come up from underneath the pan and which screw into a metal plate. We thought this would release the siphon, and indeed it can now rotate a few degrees either way about a vertical axis, bur we want to take the siphon out in order to get to the flap valve, but it doesn't want to come upwards. We don't know what else to undo in order to get the siphon out. Any advice? TIA, Matthew
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the
metal
rotate a

siphon
upwards. We

AFAIK there is a big nylon nut which holds the metal plate on to the base of the syphon (just done one so I should remember - however...).
It should work like this. You assemble the cistern off the loo, including clamping the metal plate underneath using the big nut which holds the siphon into the cistern. You then put a rubber 'do-nut' under this on the downpipe from the siphon. You fit the cistern to the pan, resting everything on the 'do-nut' which cusions the cistern and acts as a seal. You pull the whole thing down with the two bolts through the metal plate. You then attach the water (and overflow if you have an external one) and you should be more or less there.
So to remove: after (optional) draining, undo the cold feed and the overflow (if fitted) undo the two metal bolts lift the complete cistern off (either drained or still partly full of water if you are in a hurry and strong). turn the cistern upside down (without getting wet) you can then remove the rubber 'do-nut', unscrew the nylon nut, remove the metal plate and the siphon drops out of the top of the cistern
HTH Dave R
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And when you replace it, use a 2 part syphon, so you don't have to repeat the procedure in five or ten years. With these, just a small stub is mounted into the bottom, with no moving parts. All the bits that go wrong, are in the second bit which screws into the first and can be replaced in seconds.
Christian.
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MatFPeters wrote:

Syphon? In the title you say flap valve! --
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jerrybuilt wrote:

I think he means the polythene flap thats inside the syphon and actually starts teh syphon process.. Costs bugger all but they're a right pain to replace because you generally have to take the whole cistern off the wall and pan and usually bolts, screws etc are well rusted
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wrote:

Just been there last week. As reported, those two bolts were well rusted. I was able to get one off because the porcelain on the toilet bowl had cracked (wasn't me guv - there were stains on the inside of the crack which meant it had been there a long time). The other one would not budge even with mole grips on each end - and Plusgas liberally applied.
The only option I had for that remaining bolt was to first grind a flat spot on the head, then drill a central hole which allowed the head to fall off - releasing the bolt.
I now live in fear of coming across a cistern where both these bolts are held in without there being cracked porcelain on one side.....
PoP
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