Can’t find toilet leak

[Billyjoe8]

Our toilet just has a constant stream of water running into the bowl.

I have replaced the whole flush mechanism (including the black bit which screws in in the middle, it’s super tight now so do not want to take it out). All seals look good etc.

There is a tiny hairline crack leading up to the seal in the ceramic, so small you can’t even feel it. Could it be this?

Thank you!


Click image for better quality!

 

[JohnD]

how high is the water level?

does it continue to run when you turn off the supply to the fill valve (not shown)?

 

[Billyjoe8]

how high is the water level?

does it continue to run when you turn off the supply to the fill valve (not shown)?

It seems to leak at any fill level, stops leaking once the tank is empty.

 

[ETAF]

i had issues with the seals and limescale , even with a new flush mechanism, happened to 2 toilets within a few weeks of each other
so i took everything out and cleaned with limescale remover and fitted new seals that i also cleaned throughly.
maybe that maybe an impact if any existing limescale or dirt in the cistern already is contaminating the seals

But where is the hairline crack on the picture - that i would expect to line, unless its just in any glaze

 

[Billyjoe8]

i had issues with the seals and limescale , even with a new flush mechanism, happened to 2 toilets within a few weeks of each other
so i took everything out and cleaned with limescale remover and fitted new seals that i also cleaned throughly.
maybe that maybe an impact if any existing limescale or dirt in the cistern already is contaminating the seals

But where is the hairline crack on the picture - that i would expect to line, unless its just in any glaze

I have managed to get a picture of the crack. Let me know what you think!

It’s at 11 o’clock, you can just about see it.

 

[ETAF]

note , i'm just a diyer, so you may get better answers from more experienced members
But what i would do now
fill the cistern to just above that black outflow pipe - so there is a small amount of water , and allow the overflow to go down the waste
so you are left with a tiny amount of water to the top of that black screw thread
Then dry the toilet bowl completely and leave toilet paper/kitchen paper all over the back of the toilet bowl, so if any water does still come down the pipe you will see the paper wet
it it gets wet , then you know its leaking from below that waste plunger part and must be
a) the black part
b) the crack
Or maybe some food dye , to see it

the water needs to be able to into the cistern outlet pipe - the crack looks like it would leak on the outside of that , and so not into the toilet bowl

I only knew i had an issue with a small leak , when i had to remove one of toilets, when I had a leak on the actual waste pipe - and when the toilet was out , we had a very slight drip from the cistern pipe itself.
then i put paper on the back of the other toilet and after a while that also got wet, hence i knew the problem on both toilets - both toilets are identical and purchased and fitted at exactly the same time , when refurbished the bathroom & ensuite.

 

[Alec_t]

There are 2 mounting bolts attaching the cistern to the pan. If water leaked past those would it run into the pan or just on to the floor?

 

[terryplumb]

Can't see the crack. Show us a pic of your flush valve and the seal that sits inside the cistern .
Is the black ring visible in your pic the do nut washer ?
Your pic appears to show the cistern bolted to the pan ,with no valve fitted, how did you remove the valve with the cistern bolted to the pan ???

 

[Billyjoe8]

Can't see the crack. Show us a pic of your flush valve and the seal that sits inside the cistern .
Is the black ring visible in your pic the do nut washer ?
Your pic appears to show the cistern bolted to the pan ,with no valve fitted, how did you remove the valve with the cistern bolted to the pan ???

If you click the image to see higher quality you should see it. The black ring visible in the comment above is what the black thing in the original picture screws into. I have this flush mechanism: Universal Dual Flush Valve https://smile.amazon.co.uk/dp/B00JB...t_i_RK4VXHYK4K4401735EQV?_encoding=UTF8&psc=1

 

[terryplumb]

To fit the flush valve ,you must seperate the pan and cistern. If you haven't done that your not fitting it properly.

 

[HERTS P&D]

Are your 'through bolts' tight enough?

Andy

 

[Madrab]

Take the cistern off, sit it on something either side (2 chairs) and a bucket underneath with the fill valve and the flush valve fitted, pour some water into it and take a look underneath, you'll soon see where it is leaking from.

 

[CBW]

Is that the flush valve seal on the wrong side of cistern? Eg, do you have a seal between the flush valve and cistern?