New modern wc just installed. Close coupled pan and cistern. Pan is
"back to wall" and cistern rests directly on top it. All connections
satisfactory except those joining the pan to the cistern.

These are not the standard connecting bolts and plate.

Two bolts go through the bottom of the cistern and screw into fixings
within holes in the back of the pan. They are designed to do this
without anything between the pan and cistern.

Supplied are conical black rubber washers (and metal washers on top) to
seal the holes in the bottom of the cistern. These leaked massively. So
I added thin plastic washers between the pan and cistern.

I have undertightened, appropriately tightened and overtightened the
bolts. One is fine but the other still leaks whatever I do.

What is the best way of sealing this connection? Fibre washers,
sealant, different conical washers (I have tried white stiffer ones
already) or what?

TIA

mjbarnard wrote:
Two bolts go through the bottom of the cistern and screw into fixings
within holes in the back of the pan. They are designed to do this
without anything between the pan and cistern.

Supplied are conical black rubber washers (and metal washers on top) to
seal the holes in the bottom of the cistern. These leaked massively. So
I added thin plastic washers between the pan and cistern.


So you've got:

###### bolt head
--##-- washer
\\##// rubber cone
=====##====== cistern floor
~~##~~ plastic washer
@@@@@##@@@@@ W.C. bowl
#### Nut

Something like that?

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from "mjbarnard" contains these words:

New modern wc just installed. Close coupled pan and cistern. Pan is
"back to wall" and cistern rests directly on top it. All connections
satisfactory except those joining the pan to the cistern.

These are not the standard connecting bolts and plate.

Two bolts go through the bottom of the cistern and screw into fixings
within holes in the back of the pan. They are designed to do this
without anything between the pan and cistern.

What about the rubber doughnut? That goes between the cistern and the
pan to seal the flush.

Supplied are conical black rubber washers (and metal washers on top) to
seal the holes in the bottom of the cistern. These leaked massively. So
I added thin plastic washers between the pan and cistern.

Can't see that those plastic washers would help. The conical washers
seal by being forced into the holes in the base of the cistern.

I have undertightened, appropriately tightened and overtightened the
bolts. One is fine but the other still leaks whatever I do.

It could be the hole is so misshapen that the conical washer just won't
deform enough to seal in which case your supplier should replace the
cistern with one that does work.

What is the best way of sealing this connection? Fibre washers,
sealant, different conical washers (I have tried white stiffer ones
already) or what?

Sealant might work but if the cistern is defective it would be best to
exchange that and get an easy seal.

Several years ago I bought a new bathroom suite from Focus with such a
toilet but neglected to install it. I actually got round to fitting the
pan to the stack this very week but I have yet to plumb in the water
supply so I don't know if mine is going to leak. I have another toilet
so there is no pressure to complete.

--
Roger Chapman

In an earlier contribution to this discussion,
mjbarnard wrote:

New modern wc just installed. Close coupled pan and cistern. Pan is
"back to wall" and cistern rests directly on top it. All connections
satisfactory except those joining the pan to the cistern.

These are not the standard connecting bolts and plate.

Two bolts go through the bottom of the cistern and screw into fixings
within holes in the back of the pan. They are designed to do this
without anything between the pan and cistern.

Are you sure? I have a similar one, but mine has nuts under the cistern to
compress the sealing washers. Then the threaded ends of the bolts pass down
through holes in the pan, with further nuts underneath. Are yours not like
this?
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

Thanks to everyone so far.

Chris - the connection is exactly as you describe, except the bottom
nut is actually built into the hole in the pan.

Roger - the doughnut works fine. It is actually a special very soft one
supplied with the wc. Somewhat thinner and softer than the usual ones.
However I can verify that the leak is from the connecting bolts - not
the doughnut.

I agree the plastic washers shouldn't be necessary.

The hole in the pan doesn't appear misshapen. I suspect the fault lies
in the shape or quality of the conical rubber washer.

Set Square - I am sure. The nuts under the cistern do exist - but they
are incorporated into the holes in the pan. It is a modern designer
type of wc - there is a flat bottom to the cistern which sits exactly
on an exactly equivalent flat ledge on the pan. The pan extends right
back to the wall. There is no room for anything in between. Originally
I tried larger plastic washers between pan and cistern - but the
cistern became unstable - all of it's bottom sits level on the pan.

mjbarnard wrote:
Chris - the connection is exactly as you describe, except the bottom
nut is actually built into the hole in the pan.


###### bolt head
--##-- washer
\\##// rubber cone
=====##====== cistern floor
~~##~~ plastic washer
@@@@@##@@@@@ W.C. bowl
#### Nut

So the cone has to compress onto the bolt (hope it's not a set bolt -
does the thread go all the way up to the head?) as well as the cistern,
else it won't be watertight. Not a lovely design IMO. The plastic washer
won't help a lot, as of course water may pass it (between the bolt and
washer) and seep through the threads of the captive nut. Does the cone
fit tightly onto the bolt shank? If not, can you use a larger bolt (if
you can replace the captive nut)? Could you use silicone to stick the
cone onto the bolt, let it go off, and then do up the bolt with more
silicone to seal it? 1/8" PTFE gland packing?

Yes the cone has to compress as you say. The thread does go all the way
up.

Agree not a great design. You wouldn't believe what it cost! I think
the design is attributable to the 'back to wall' nature of the pan. The
back of the wc is not accessible once installed, so the design allows
removal/connection of the cistern to pan from the front/top without
pulling the wc away from the wall.

Not quite sure what 'tightly' means. It appears a close fit - but the
cone definitely feeds very easily over the bolt.

I could use a larger bolt - but am a bit wary of removing the captive
nut. It is actually not a nut but a piece of metal with appropriately
sized screw hole for bolt with metal wings underneath which stabilise
it within its hole. If I remove it and fail - I might be worse off.

I could use silicon exactly as you describe. I might try this next.

Not sure what gland packing means?

mjbarnard wrote:
Yes the cone has to compress as you say. The thread does go all the way
up.

Sounds like time to change the bolts - difficult, sealing to
the thread...


Agree not a great design. You wouldn't believe what it cost! I think
the design is attributable to the 'back to wall' nature of the pan. The
back of the wc is not accessible once installed, so the design allows
removal/connection of the cistern to pan from the front/top without
pulling the wc away from the wall.

Not quite sure what 'tightly' means. It appears a close fit - but the
cone definitely feeds very easily over the bolt.

A close fit should be OK, bearing in mind that the shank of the
bolt needs the cone to compress onto it.


I could use a larger bolt - but am a bit wary of removing the captive
nut. It is actually not a nut but a piece of metal with appropriately
sized screw hole for bolt with metal wings underneath which stabilise
it within its hole. If I remove it and fail - I might be worse off.

I could use silicon exactly as you describe. I might try this next.

I should try to get another bolt (not a set bolt) - what's it made
of, BTW?


Not sure what gland packing means?

Stuff that's used to pack glands, where a shaft goes through. Like
a piece of cord, but made of PTFE, about 1/8" in diameter (these
yanks!). Wind it around the shank of your new bolt to replace the
cone. Just a possibility.

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from "mjbarnard" contains these words:

Not quite sure what 'tightly' means. It appears a close fit - but the
cone definitely feeds very easily over the bolt.

FWIW the cones on mine are quite a tight fit on the thread. If the leak
is down the thread rather than round the outside of the cones then
silicone sealant on the thread should give an effective seal.

--
Roger Chapman

mjbarnard wrote:

Thanks to everyone so far.

Chris - the connection is exactly as you describe, except the bottom
nut is actually built into the hole in the pan.

Roger - the doughnut works fine. It is actually a special very soft one
supplied with the wc. Somewhat thinner and softer than the usual ones.
However I can verify that the leak is from the connecting bolts - not
the doughnut.

I agree the plastic washers shouldn't be necessary.

The hole in the pan doesn't appear misshapen. I suspect the fault lies
in the shape or quality of the conical rubber washer.

Set Square - I am sure. The nuts under the cistern do exist - but they
are incorporated into the holes in the pan. It is a modern designer
type of wc - there is a flat bottom to the cistern which sits exactly
on an exactly equivalent flat ledge on the pan. The pan extends right
back to the wall. There is no room for anything in between. Originally
I tried larger plastic washers between pan and cistern - but the
cistern became unstable - all of it's bottom sits level on the pan.

doesn' th erubber washer go bteween the cistern and the pan with the
plastic washers inside the cistern?

Anyway, the answer is a ****load of silicone sealant - between pan and
cistern and between washer and cistern base. finger tight, leave 24
hours, then tighten fully on custom made silicone rubber gasket...