Tap connector isolator leaking on bottom fill cistern

stytagm

Hi All,

I was trying to replace a failing fill valve in my cistern, I got the old one out no problem, adjusted the new one, popped it in - carefully hand-tightened the nut - and as per the instructions - let the water back in to check the seal. It leaks (sprays) from the bottom of the metal nut that joins onto the plastic threaded cistern valve.

The metal nut at the top of the isolator valve still has some play (relative to the valve) after it's finger tight on the plastic thread. That can't be right surely?

A few questions:
I'm pretty sure I haven't cross threaded it - but how can I be certain?
Do I need to replace the fibre washer? Should the fibre washer push right down inside the nut - or sit just inside it on the threads?

I've got a photo - but I'm not allowed to post it (first time). If someone asks or can edit - I may be able to send it to you.

All advice gratefully received.

[Deleted User]

There are two nuts on the treaded plastic stem at the base of the valve: one plastic one that holds the valve in the bottom of the cistern, and the brass one on the end of the pipe. The first just needs enough to compress the rubber washer so that it seals inside the cistern. The brass one needs to be done up with a spanner, but not too tight!

The fibre washer sits on the end of the fitting, and is compressed between the collar and the end of the stem as you tighten the nut. Washers are usually reusable but may need renewing if they're tatty.

thescouselander

The chances are the thread on your new valve is slightly shorter than the original so the connection is not sealing properly. That said it wouldnt hurt to tighten the nut up a bit more to see if you can get it to seal.

Last time this happened to me I had to modify the water feed to the toilet by cutting back the original pipe and fitting a flexible connector.

Marktheshark

They are very easy to cross thread, you need a loose nut and hand thread it on a few times to get the thread back.
Once it goes on straight, lubricate the plastic and fit a new washer and nip it up with a spanner whilst holding the fill valve from inside the cistern.
If it is still loose, bin the idea and fit a flexi with an isolator valve built in.