Replace valve/washer/nut/seal for cistern water inlet leaking where nut meets porcelain?

ClarusDignus

The outside of my toilet cistern is dripping where the water inlet connects to the cistern and push valve, specifically, where the plastic nut (the one tightened by hand) meets the porcelain.

There appears to be a sealant applied to where the plastic nut meets the porcelain (see photos) and the drips appear to be coming from this sealant.

What do I need to replace to fix this? The valve, the washer, the nut, and/or the sealant?

The cistern is empty. The push valve is held by a string to prevent refilling. When I'm replacing any parts, I'll be sure to turn off the water supply.

NSG666

The white nut should be tightened with a spanner not just hand tight. But don't go too mad or it will split.

Now that the cistern is empty, if you dry it off does it get wet again? If so it could be the joint with the brass nut. If not then it's the plastic nut.

FreeBear

A pair of replacement rubber washers is needed. Clean off all that white gunk, fit a new washer either side of the porcelain. If sealant is needed, only the thinnest of smears is required. Use an adjustable spanner to tighten the nut. Hand tight is never going to be enough. You only need it tight enough to compress the rubber and stop any leaks, it does not need to be gorilla tight (maybe 1/4 turn from hand tight).

ClarusDignus

NSG666 said:

The white nut should be tightened with a spanner not just hand tight. But don't go too mad or it will split.

Now that the cistern is empty, if you dry it off does it get wet again? If so it could be the joint with the brass nut. If not then it's the plastic nut.

Yes, the dripping is still occurring at the same point (see photo) since I emptied the cistern about 12 hours ago. I've dried the white nut and all other areas every few hours to determine where the drips are emerging from.

In the following photo I just took, there's a water drop at the right of the white nut. The wetness on the floor (or the inside of the bucket I now have underneath it), indicates it's continuously dripping.

Grenage

It looks like the inlet isn't flush with with the pan, likely because it wouldn't line up with the pipework and they bodged it with sealant.

I'd probably do as Freebear suggested, but I'd cut the feed pipe back and attach a flexible connector to link the inlet and feed.

Well I'd personally adjust the feed so it lines up, but a flexible connector is easier.

NSG666

It's difficult without being on-site but it looks like the cistern is empty and dried out yet there is still water showing on the white nut securing the inlet valve to the cistern.

The joint with the brass nut might be leaking and spraying water (almost invisibly) onto the plastic nut but it's possible that the feed pipe has been pulling on the inlet valve and over a period of time it has started to split on the threads in the area of the white nut.

It might be as simple as FreeBear has said but if you can do it yourself, it might be worth spending a few extra £s and buying a new inlet valve with a metal shank - see link (I think Screwfix sell them too) These are excellent as it's pretty impossible to cross thread when fitting/connecting to them.

Viva Skylo Bottom Entry Fill Valve Brass Shank (toolstation.com)

ClarusDignus

Grenage said:

It looks like the inlet isn't flush with with the pan, likely because it wouldn't line up with the pipework and they bodged it with sealant.

I'd probably do as Freebear suggested, but I'd cut the feed pipe back and attach a flexible connector to link the inlet and feed.

Well I'd personally adjust the feed so it lines up, but a flexible connector is easier.

What's the advantage of a flexible connector? Should I get a tap or hose connector?

NSG666

It looks like the grey pipe that's been painted white is quite tight and pulling on the inlet valve. Grenage has suggested the easiest solution to effectively increase the length and relieve the stress on the joint.

If the pipe is tight and you use a flexi hose then you'll need a 15mm x 1/2" and make sure it's WRAS approved as there is some cheap rubbish out there (even from the majors)

Hose 15mm x ½" x 300mm | Compression Hoses | Screwfix.com

Use the existing pipe support.

Section62

ClarusDignus said:

What's the advantage of a flexible connector? Should I get a tap or hose connector?

A flexible connector reduces the stress on the plastic tail of the valve and removes one potential source of leaks.

However, it looks like the main problem is higher up than that.


Can you post a picture showing the whole of the supply pipe - the first picture in the thread shows the pipe curving away down off the bottom of the picture.

As the pipe appears to have been bent to that shape you will have a tough job getting any kind of connector to make a watertight joint with the supply pipe - other than at the end (where the grey plastic elbow connector is), or lower down (out of shot) if the pipe straightens up.

In this case by trying to fit a flexible connector you could end up making a new and bigger problem for yourself.

NSG666

Section62 said:

ClarusDignus said:

What's the advantage of a flexible connector? Should I get a tap or hose connector?

A flexible connector reduces the stress on the plastic tail of the valve and removes one potential source of leaks.

However, it looks like the main problem is higher up than that.


Can you post a picture showing the whole of the supply pipe - the first picture in the thread shows the pipe curving away down off the bottom of the picture.

As the pipe appears to have been bent to that shape you will have a tough job getting any kind of connector to make a watertight joint with the supply pipe - other than at the end (where the grey plastic elbow connector is), or lower down (out of shot) if the pipe straightens up.

In this case by trying to fit a flexible connector you could end up making a new and bigger problem for yourself.

I thought that painted pipe was plastic but having looked again I think that you are right.

Section62

NSG666 said:

I thought that painted pipe was plastic but having looked again I think that you are right.

I wasn't totally sure either way. I was hoping another picture might be clearer.

If it is copper which has been attacked with the aid of a bending spring there will definitely be a problem making a joint part way along.  If it is plastic and has been like that for years there could be some deformation of shape, plus the paint will cause issues with push-fit.

Not insurmountable problems... but not something I'd suggest an inexperienced plumber should embark on unless absolutely essential to the job.

If the pipe does straighten up before going into the floor(?) there is at least scope to get a good join somewhere if necessary... without needing to lift floorboards.