Replaced toilet flush valve - now leaking isolator nut

[OasisFan79]

We replaced the flush valve in one of our toilets today. Everything went ok until we put the water back on.

When we put it back on water began to leak quite quickly from underneath the isolation valve nut (as indicated in the photo below).

So we isolated the water again.

We tightened the isolation valve nut as tight as we could by hand (wearing rubber grip work gloves), however even with the water isolated water still dripped out (only dripping this time).

We then loosened the isolation valve nut by a small amount which stopped the drip, however if we turn the water back on, it pours out again from the same place.

We don't really want to have to call a plumber out because we've got this far by ourselves.

Is there anything we could have missed? Should we have a changed a washer somewhere as well?

 

[Newboy]

A new fibre washer in the service valve https://www.screwfix.com/p/arctic-products-prestex-tap-connector-washers-5-pack/1109j

or possibly the tail of the new fill valve is slightly shorter than old one/the new valve hasn't been tightened enough - the same net effect

 

[OasisFan79]

Thanks - much appreciated. We’ll pick some of these up from Screwfix tomorrow and get one fitted.

 

[OasisFan79]

Got some of those washers today and fitted one tonight.

Unfortunately it still leaks just the same.

I don’t think it’s the length of the tail at fault as there’s plenty to screw into.

Could it be that I’m not tightening the nut enough? I can only do it hand tight as it’s impossible to get a spanner round it due to the confined space.

 

[terryplumb]

Got some of those washers today and fitted one tonight.

Unfortunately it still leaks just the same.

I don’t think it’s the length of the tail at fault as there’s plenty to screw into.

Could it be that I’m not tightening the nut enough? I can only do it hand tight as it’s impossible to get a spanner round it due to the confined space.

Hand tight is just not good enough I'm afraid. You must use a spanner.

 

[Keithmac]

Buy a cheap spanner and cut it in half of you have to, even a stumpy spanner will give you enough leverage..

 

[OasisFan79]

I bought a basin wrench from Screwfix. Just the job. Tightened it up and no more leaks.

Another one of those jobs where it’s easy if you’ve got the right kit.

https://www.screwfix.com/p/basin-wrench-11/14631