Leaking seal - toilet cistern inflow pipe

[The Incredible Hulk]

Dear all, after seeing the appearance of a dreaded water mark on the living room ceiling I traced the fault to a leak where the fill valve unit goes through the cistern to join the inflow pipe (apologies if I’ve got the names wrong). I emptied the cistern and installed a new fill valve unit making sure the seal met with the hole in the bottom of the cistern. Job done I thought, nope. Drips appearing at the exit hole where the fill valve exits the cistern. I’ve tried to resitting it and still the dripping occurs. My plea, am I missing something that means the rubber seal doesn’t mate with the bottom of the cistern and therefore leaks? I’m going to have another go at resitting the flow valve but in all honesty that feels like a busted flush (no pun intended). Grateful for any help / advice. Cheers, Kevin.
PS fill valve is a fluidmaster.
PSS - leak seems to be between the plastic nut and the cistern.

 

[Harry Bloomfield]

PSS - leak seems to be between the plastic nut and the cistern.

Try some Plumbersmait, between both sides of the soft sealing washer, which goes inside the cistern.

 

[just pumps]

Remove water from inside the cistern and dry around the area where the hole is. Remove, clean and dry the rubber sealing washer on the valve. Apply a bead of silicone on the rubber seal and install tying to hold the valve to stop it moving around whilst attending to the nut underneath.

 

[HERTS P&D]

Try and tighten it up.

Don't use plumbers mait.

Andy

 

[oldbuffer]

1. As "Just pumps" above.
2. If that doesn't work, then check to see if the underside of the cistern has water tracking across:
2.1 From the point where the flush pipe exits. AND / OR
2.2 If it is a close coupled WC and the cistern is fastened to the pan with two small bolts through the bottom of the cistern, from either bolt.

 

[Harry Bloomfield]

1. As "Just pumps" above.
2. If that doesn't work, then check to see if the underside of the cistern has water tracking across:
2.1 From the point where the flush pipe exits. AND / OR
2.2 If it is a close coupled WC and the cistern is fastened to the pan with two small bolts through the bottom of the cistern, from either bolt.

When sealant has failed to seal, my last resort is the PlumbersMait. It has never, ever failed, though it is by no means as easy to use, it gets absolutely everywhere, but it's easy to clean off. It oozes out of the joints, as the joints settle.

I tried everything, trying to get the plug hole, to seal properly against my downstairs toilet wash basin. Nothing I tried worked, or worked for long. Mait did it in one. I likewise had a similar problem with the toilet cistern, again, Mait fixed it in one attempt.

 

[HERTS P&D]

My advice is to listen to a plumber and not a diyer!

Andy

 

[Harry Bloomfield]

Just to be clear - there is a world of difference, between the tools and materials those in the trade have, versus those simply doing a bit of DIY. For instance PlumbersMait is none setting and can be kept unused in the pot, for decades. A tube of silicone will set in the tube and can become useless in a matter of months, so the suggestion to use silicone sealer, might be a good one, for someone facing such problems regularly, as the will likely use the tube up, but a less useful idea for the DIY'er. Before these materials came along, the plumbers would be using string and putty.

So a small tub of Mait is well worth the investment for someone doing repairs at home.

In the electrical section, I often see DIY'er, seeking help with their problems, particularly with RCD tripping issues. Eric almost always pipes up with is advice of you must have this, that and the other, to diagnose such problems, basically thousands of pounds worth of test equipment, all great to have, and I do have it, but I never get out, or suggest getting out the 'heavy artillery' as a first step. Better to help a DIY'er fix his/her problem, with what they might have, or easily have access to.

 

[The Incredible Hulk]

Thanks all for your support. I followed @just pumps advice and all good.