Toilet keeps filling

I would just replace the whole thing ......

Yes, they're very cheap.

Fair enough but the thing is kind of "built-in" so getting to the underneath of the cistern could be a serious challenge!

You need to replace the ballcock, not get underneath the cistern.

I'm sure after a clean it would be fine.

Other wise there's a lot more undoing, sealing etc.

The only concern I might have if that there might be a wear groove in the valve washer seat, in which case I might agree a replacement is the best way.

I need to get under the cistern to replace the ballcock as it's mounted on the bottom of the cistern not the side ie the water comes in underneath

The OP's "ballcock" is a unit that includes the filling aspect that attaches to the bottom.

Different internals will not generally be compatible.

More or less. If you turn the water off, unscrew the blue bit, you may well find that it?s just a tiny bit of grit in the valve stopping it sealing. Certainly well worth a look and cleaning out before you spend any money.

Tim

n the bottom of the cistern not the side ie the water comes in underneath

no no no. You just undo the big blue plastic nut in the photo, and the ball & arm come away. Replace the rubber washer/diaphragm with the right type, there are several, and put the ball/arm back in place & refit the nut. Then just check the water level it fills to is ok.

I assume you know to turn the water off first :)

NT

Looked at the picture, and as I suspected, it's a Torbeck valve. These are very prone to grit and dirt. Whenever they do work on the underground water pipes round here, there's a chance that ours will do this.

Turn off the water supply (with luck there's a service valve in the cistern feed). Remove the blue ring (probably very stiff) and withdraw the body of the valve. There's a flat rubber washer with a white plastic spike and a tiny hole with a plastic insert; that may be left behind, in which case pull it out. Clean that all thoroughly. Use a water pistol or something to wash out the housing attached to the cistern.

Gently unclip the swinging part of what you removed. Blow through the tiny hole; I use canned air. Wash it all thoroughly.

Clip the swinging part back on. re-seat the rubber washer; the hole in it fits over a little metal pin in the housing; get this right or you'll puncture the washer. Replace housing and blue ring. It often has to be done up quite tight.

Turn the water back on. If necessary, rotate the float on its 'screw thread' to set the correct water level.

Make sure there are no leaks between the housing and the valvel body; if there are, do the blue ring up a bit more.

If it still overflows, it's worth another go. Otherwise, new washer or valve!

It's not actually a ballcock. No ball.

It's a Torbeck valve.

It looks that the pivot end of the float arm has been inhibited by the build up of limescale. Possibly and simple application of a limescale remover around that area will restore proper operation.

Since its a bottom fill, and there will be nuts that need undoing under the cistern, he would need to get there.

This is a common fault with this sort of float valve. There is a diaphragm inside with two tiny holes The one nearer to the edge is blocked. This stops the valve from closing (it uses water pressure to close.)

Unscrew the blue ring, remove the diaphragm and clear out the hole. Replace it making sure the needle is correctly located in the centre hole.

The usual faults on normal ballcock or float valve designs are usually. 1. the valve or its washer is scaled up or in some other way knackered. the ballcaock or float has a hole in it which makes floating a challenge! In the first instance establish if you have a loft tank fed or a mains fed system and buy a whole new valve assembly with the right sized hole, i.e. big hole loft tank little hole mains fed. Also do not even consider those with most of their parts made of plastic, they are rubbish and trying to make the pipe join leak proof has driven many a DIY er to drink. If its the float, If its not in too bad a nick and you can see the leak site. let it drain or evaporate and mend the hole with something like epoxy resin and then refit. Otherwise you need a spare and this may or may not still be available depending on the design. I also hate plastic bits joining this with the valve as they have just snapped for no reason other than its crap.

Brian

Brian - you won't be able to see the picture, but it's a Torbeck valve, not the usual ball valve.

I have posted a comprehensive set of > The usual faults on normal ballcock or float valve designs are usually.

True enough if he needs to replace the whole assembly. However, he might be able to replace the blue part containing the diaphragm if it's anything like my side entry FluidMaster valve where that bit can be removed with a quarter turn or less twist for servicing (I've got an identical FluidMaster stored as a spare - the original that was swapped out for one recovered from the downstairs shower room toilet cistern when we had the whole lot revamped 6 or 7 years ago). It looks like I might do better to swap it back, now that I've modded the air break vent cap to prevent the stuck air break valve from allowing water to spray out past the cistern lid during each filling cycle[1].

Either way, he'll still have to shut off the water feed. I still haven't found a round tuit to fit a shut off valve in the feed to our half landing toilet cistern to save me having to run down to the basement stopcock and back... TWICE! each time I need to seriously fettle the FluidMaster valve which is currently allowing the water to slowly seep past its diaphragm valve, causing a slow but annoying drip from the overflow.[2] :-(

One thing I do notice in that picture, is the unblanked/unsealed side entry hole just to the right of the valve (which is of even greater concern than the absence of a fixing nut on the flush handle bearing shaft). This looks like an 'overflow accident waiting to happen' on an even larger 'Biblical Scale' than my own[2]. It doesn't even seem to have ever been blanked (preferably sealed) off in its recent history. Unless the overflow outlet is barely above the current fill level, that *does rather* look like a disaster waiting to happen, imo.

My original 'Quick Fix' solution had been the use of a shaped aluminium foil pie dish placed over the top of the vent dome to act as a spray deflector but this was a little tricky to fettle up just right and risked fouling the float arm so a tentative drilling out of the nipple port on the 'spare' to confirm my suspicion about this "ornament", inspired me to the current hot glue/drill-out/tubing fix.

It was a problem that arose as a consequence of the float slide becoming contaminated by iron filings from all the hacksawing required to undo the seized clamp that had held the failed siphon lever arm onto the flush handle spindle. Of course, I didn't discover *this* until a day or two