Urgent: Close couple toilet issue

Silicone is belt and braces. Sometimes if the cistern surface isn't dead flat its hard to get a seal.

Try it without if you have the time, and if it leaks do it again with. Be sure to remove all the old crap first and check that sealing surfaces are not damaged in any way

I think I used silicone on quite a lot of my 'doesn't need sealant plumbing. Especially the soil pipe to U-bend joints

I can't remember about the flush mechanisms, but ISTR one needed it

I fitted a complete new pan + cistern about 2 years ago, no silcone. Also had to replace rusted bolts and broken plastic washers connecting another one, again no silicone.

I replaced ours dry with no problems so far. Much easier than I thought it would be.

I have found silicone on newly installed toilets when replacing the siphon due to me being clumsy trying to remove a calcium build up. I can't actually see why you would do this this joint isn't under high pressure.

I always replace dry and have never been able to detect any leakage subsequently.

Dave

The bog is up and working flushing nicely but I had to resort to silicone on the siphon, I found out why it was gobbed on previously, the hole in the bottom of the cistern was quite a sloppy fit for the standard 1.5” outlet pipe. Centring the pipe and the sealing washer was quite hit or miss especially with the coupling plate in place. The doughnut was left dry and it sealed fine with the pan. Thanks to all who contributed.

Richard

You may find with the siphon, joining kit and donut that the instructions say don't use any additional sealer.

Last month I replaced the flushing mechanism in two close coupled toilets. It was a complete PITA with the amount of sealant that had been added previously*. After spending too long removing all the sealant both were re-assembled using new parts and only the supplier rubber washers. Result - no leaks.

It is false economy to use the old joining kit and donut. The donut will have deformed and possibly gone a bit brittle and WILL leak if used again.

It should be noted that on Facebook/Youtube there are videos of siphons being fitted with masses of sealant. In all the videos I've seen where this has been done a 1.5 inch part has been fitted to a cistern with a 2 inch hole. Just use the correct replacement part. I see that Screwfix also has a 1.25 inch part.

I've fitted this type of flushing mechanism to one of the toilets.

The flush push button or handle is joined to the flush mechanism by a dual cable which is easily demountable for maintenance purposes. I used the dual push button but from memory the mini handle is lift up for short flush and push down for long flush.

Some fitters use silicone sealant as a matter of course. Personally I don't use it as it makes disassembly and replacement harder. I usually smear the mating surfaces with silicone grease. This eases assembly and enhances the seal, but is non setting. Also it won't attack rubber or plastics.