How to secure a toilet cistern overflow pipe?

Purple-flower

Hello everyone, merry Christmas!

I've been doing some small repairs to the toilet but I've encountered a small problem. I had to change the water inlet system and also the overflow pipe as they were old and misbehaving. The water inlet is fine and secure but the overflow pipe is leaking (very slowly but still leaking) from under the cistern? I have tightened the nut as much as possible from underneath and the washer is brand new. Any ideas how to stop the leak? In an hour it has dripped about a teaspoons worth of water just to give you an idea of how slight the leak is. Thank you

Stooby2

Have you got the rubber washer on the inside or outside? It should be inside. Might be worth redoing it to make sure it's not pinched, got dirt there etc.

DevCoder

Use the old bodge PTFE tape

Purple-flower

Thank you for your replies

Stooby2 wrote: »

Have you got the rubber washer on the inside or outside? It should be inside. Might be worth redoing it to make sure it's not pinched, got dirt there etc.

The rubber washer is inside the cistern, but I may take it out and give the whole area a clean

krisdorey wrote: »

Use the old bodge PTFE tape

Would using silicon sealant help if I put it between the washer and overflow pipe in the cistern? I've heard rumours about PTFE tape

Stooby2

It should seal perfectly well with the washer. The best way is to get the cistern dry and completely clean before it's installed. It's easy for dirt or scale to cause an issue.

If at the end of the day you're still getting a leak, then a thin layer of sealant on either side of the washer, in a completely dry cistern might help. Make sure you leave it to cure for the full time stated on the tube.

mttylad

Take it apart and redo it completely, with new washers etc.

plumb1_2

DONT use silicone sealant on rubber washers as it will ruin them.

southcoastrgi

plumb1 wrote: »

DONT use silicone sealant on rubber washers as it will ruin them.

I've never had a prob & i always use mastic on them

Ruski

+1 with SCrgi

DevCoder

Most silicone sealants release acetic acid whilst curing which will attack the rubber. This is why silicone sealant smells of vinegar when curing.

Whether this will cause the rubber to fail is another question.

plumb1_2

southcoastrgi wrote: »

I've never had a prob & i always use mastic on them

silicone will make the rubber go soft and will twist. There is not need to use silicone when the rubber will do fine, that's why it is supplied by the manufacturer with all overflows and ball-valves.