WC Siphon oulet size

[sid]

Old toilet siphon was u/s so I purchased a new unit. However, the outlet diam in the cistern is approx. 5mm bigger than "new" units and despite a lot of effort it is leaking at a fair rate when I screw together.

Apart from buying a new cistern, is there an adapter to bridge this gap.

Or any other fixes?

I have fitted an oversize plastic flange at the base of the outlet pipe to bridge this gap and also used some silicon sealant to try and stop the flow. However, this a bodge at best and I have not tried it as yet as I am leaving the sealant to cure.

Any advice appreciated

[BigWallop]

A 5 mm difference shouldn't be that bad. Do you mean a difference in size to the total outside diameter of the hole to the outside diameter of the flange on the new syphon unit?

Make sure you have the big firm rubber washer on the inside of the cistern, around the thread of the syphon unit, first. That way, when you tighten the big locking nut on the outside (bottom of the cistern) it won't turn the washer and cause leaks. The big firm rubber washer should be able to take a difference in size of up to 5 mm with no problem. Once it's squashed into the hole by the syphon unit on top and the big lock nut on the bottom, it should be sandwiched tight enough between the inside of the cistern and the syphon to create a good seal.

The soft spongy foam washer sits around the thread once the new syphon is fitted to the cistern. This soft foam washer creates a seal between the bottom of the cistern and top of the loo bowl.

Hope this helps a bit. Good luck with it.

[sid]

No soft spongy foam washer included with the siphon kit ! I salvaged another top washer to apply to the bottom of the bottom of the cistern. The flanges and silicon sealant were also applied as belts and braces because by then I had drained the cistern 3 times and was heartily sick of it all.Not a drip in sight but it does make me realise how little stands in the way of getting a flood of water.

Took a look at B&Q siphon packs and they all say "for modern cisterns 38mm" Bathroom suite must be over 30 years old - hardly modern.

Thanks for your help.