Toilet Leak

My toilet has developed a leak from the bottom entry inlet valve and I am looking for some advice.

On close inspection the leak was coming from the connection between the copper pipe and the plastic tail of the inlet valve.

A quick trip to wickes and I got some new fibre washers. I removed the inlet valve and cleaned the tail throughly. Cleaned all the copper connection and dampened the new fibre washer.

Once fitted up the leak stopped- job done, or so I thought...

Over the next few hours I kept checking on the connection and it appeared to be damp again.

It started dripping more regularly and since originally refitting the connection I have nipped it up on two occasions. I have been aware not to over tighten the connection due to it being a plastic tail but I fear the two extra nips have made the leak worse.

As a side note, although I did remove and refit the inlet valve without replacing the seal, it definitely isn’t leaking from there.

I read that it’s best not to put any sealant but on the other hand I’ve read that people can’t get them to seal without any sealant.

My question is if I am to try a sealant, am I best to use silicone sealant, ptfe tape or plumbers mait?

Thank you

Did you clean off all traces of the old fibre washer from the tap connector , before fitting the new one.
Do you have the correct seal ?
Are you sure it's not leaking from above ,and collecting on the tap connector ,leading you to the wrong conclusion ?

Mother in Law's WC has done exactly the same thing, been there 20 years plus, and this week decided to start leaking. New washer didn't work, so I've cut a bit of the copper out and fitted a flexi in it's place. She's not phoned me to say her carpet is still wet so fingers crossed, otherwise I'm going to have to change the ball valve as well.

Rob Gooch said:

plastic tail of the inlet valve

Click to expand...

Rob Gooch said:

but I fear the two extra nips have made the leak worse.

Click to expand...

Could it be cross threaded??

If so time for a new fill valve with brass tail.

Rob Gooch said:

My toilet has developed a leak from the bottom entry inlet valve and I am looking for some advice.



It started dripping more regularly and since originally refitting the connection I have nipped it up on two occasions. I have been aware not to over tighten the connection due to it being a plastic tail but I fear the two extra nips have made the leak worse.

As a side note, although I did remove and refit the inlet valve without replacing the seal, it definitely isn’t leaking from there.

I read that it’s best not to put any sealant but on the other hand I’ve read that people can’t get them to seal without any sealant.

My question is if I am to try a sealant, am I best to use silicone sealant, ptfe tape or plumbers mait?

Thank you

Click to expand...

If you didn`t hold the valve tight in postion whilst nipping up underneath then the valve stem might have moved breaking the seal in the cistern. Remove the valve, remove old silicone and refit the valve with new silicone under the bottom collar.
Trace start of leak using dry tissue paper and start at highest point.

Thanks for your replies, it’s not leaking from the cistern base- I’ve just checked that with toilet paper and it’s bone dry.

When I was assembling it, it didn’t feel cross threaded, and I have crossed threaded stuff before so I know how it feels if that makes sense.

I got a bigger adjustable spanner and gave it one more nip before I take it all apart.

So far, so good and it’s still dry, we shall see how it goes, if not I will source a new inlet valve with brass tail and try again.

One thing to check with plastic tails is that the end face is perfectly flat. I've known a plastic tail to have a moulding imperfection which needed smoothing off to prevent a leak.

Also depending on age, I’ve seen them with hairline cracks in them, sometimes form over tightening.

Update:- I went to wickes to get a new inlet valve with a brass tail but they had no stock.

As a last ditch attempt i bought a tube or fernox ls-x to use with my current plastic tailed valve and, voila, no leak for 24 hours.

Thanks again for your comments and tips.