Monobloc tap unable to tighten on ceramic sink

[johnbuckley]

Monument do a "Stickfast" washer to help in such situations. See BES Item No. 19700. However, if it really requires their installation tool it's not worth it for a one off.

Interesting idea, quite expensive for a round, double sided sticker, it would make the o ring redundant so guessing the sticker would be a good enough seal. May have to resort to this if using a brass nut doesn't help.

 

[opps]

Had a quick look at that and the area that the o ring would sit is nice and flat, no dipping.
I'm hoping that, due to the design of the tap, I just can't tighten it enough whilst under the sink; so swapping for a brass nut will help

You might need a basin wrench.

Google Search

You may also find it easier to remove the basin to fit the tap.

 

[johnbuckley]

You might need a basin wrench.

Google Search

You may also find it easier to remove the basin to fit the tap.

Had one of those and can I find it; not a chance!
Waiting for brass back nut to arrive; once I know the nut size I'll prob pick up a box spanner somewhere.
In hindsight I would have fitted the tap to the sink prior to installing it but it was heavy enough being a 1 1/2 bowl ceramic so took the wimps option and decided to fit the tap after! All siliconed in now as I never expected the tap to give me grief; ho hum.

 

[Scally-Ho]

I hope you find a brass back nut with the correct thread. In my experience (I'm 82) nearly all plumbing back nuts are or were threaded BSP (British Standard Pipe thread) and anything else is down to perseverance and/or luck. If you can't find a basin wrench, then a box spanner will serve you equally as well.

 

[opps]

Had one of those and can I find it; not a chance!
Waiting for brass back nut to arrive; once I know the nut size I'll prob pick up a box spanner somewhere.
In hindsight I would have fitted the tap to the sink prior to installing it but it was heavy enough being a 1 1/2 bowl ceramic so took the wimps option and decided to fit the tap after! All siliconed in now as I never expected the tap to give me grief; ho hum.

Fair enough. For what it is worth, I couldn't fight my way out of a paper bag. My journeys home are exaggerated as I cross the road to avoid paper bags.

Regarding the box spanner. That will need to be a really wide box spanner and to fit the tommy bar into it, it will have to be a really long box spanner.

Best of luck.

 

[Scally-Ho]

Fair enough. For what it is worth, I couldn't fight my way out of a paper bag. My journeys home are exaggerated as I cross the road to avoid paper bags.

Regarding the box spanner. That will need to be a really wide box spanner and to fit the tommy bar into it, it will have to be a really long box spanner.

Best of luck.

Yes indeed, plumber's box spanners are both long and also wide enough for standard back nuts. Just a few as an example below as I do not possess an intrussive smart phone to photograph my old Monument set

 

[opps]

The tap side of the ceramic

The o-ring is rubber. The washer is nylon (or at least it seems to be).

Surely the point of the o-ring is to compress and provide a watertight seal? The nylon washer will not provide a watertight seal.

 

[opps]

Yes indeed, plumber's box spanners are both long and also wide enough for standard back nuts. Just a few as an example below as I do not possess an intrussive smart phone to photograph my old Monument set
View attachment 382994

Those would be fine for the back nut on the type of fitting which has a brass crescent and 8-13(?)mm nut, but I suspect the OP would need a significantly larger box spanner. Monument, and others, do sell larger box spanners individually but in the case of monument, if it too short, they seem to need additional attachments.

That said, I might be wrong.

 

[CountryFan]

The o-ring is rubber.

Yes I know

The washer is nylon (or at least it seems to be).

Both look rubber imo, but could be poor photo

Surely the point of the o-ring is to compress and provide a watertight seal?

The O-ring is to prevent water egress

The nylon washer will not provide a watertight seal.

I didn’t say any nylon washer would provide a water tight seal. Granny and egg sucking springs to mind here.

 

[opps]

Yes I know

Both look rubber imo, but could be poor photo

The O-ring is to prevent water egress

I didn’t say any nylon washer would provide a water tight seal. Granny and egg sucking springs to mind here.

Sorry, I no way was I intentionally being condescending. I simply could not understand why the tap would have an o-ring on the underside if not to make it watertight to the "worktop". I do not understand why an additional washer would be necessary, it seems to negate the need for the o-ring.

Having read many of your posts, I appreciate that you know more about plumbing than me. If I see advice that I do not understands I will question it. Again, no offence intended.

 

[johnbuckley]

Ok so, on my second back nut and neither fit, first one 32mm and slightly too small in diameter although thread seems to be the same, second one a 1" seems to have correct diameter but thread far too course so neither any good. Off to plumbers merchants tomorrow with tap in hand to see if they have the correct nut.
To answer some of the above, yes the o ring at the base of the tap is rubber and as far as I know should create the seal/grip for the tap body. The washer underneath the sink is rubber followed by a steel washer.

I'll pick up a box spanner to fit easy enough, as soon as I can source the damned nut! Hopefully this issue is actually down to not enough torque being able to apply to the nasty supplied nut with plastic body. Never had this problem in the past but then I've never had a ceramic sink either, not that the type of sink should be the problem.

 

[johnny2007]

I had the same problem with my old kitchen sink and tap.
That stupid backnut that it's supposed to be tighten by hand is a very poor design.
I ended up putting some Soudal silicone between sink and washer on the underside of the sink.
It helped tightening a bit better and once dry it never moved for 17 years.
When I removed it, as I had to re-,use the tap in a garage sink, I gripped the undernut with plumbers pliers and twisted the tap body from above.
It took a bit of force but it came off pretty easily.

 

[johnbuckley]

I had the same problem with my old kitchen sink and tap.
That stupid backnut that it's supposed to be tighten by hand is a very poor design.
I ended up putting some Soudal silicone between sink and washer on the underside of the sink.
It helped tightening a bit better and once dry it never moved for 17 years.
When I removed it, as I had to re-,use the tap in a garage sink, I gripped the undernut with plumbers pliers and twisted the tap body from above.
It took a bit of force but it came off pretty easily.

Thanks for that; yes, using some silicone and letting it cure is something I've considered too

 

[CountryFan]

Sorry, I no way was I intentionally being condescending. I simply could not understand why the tap would have an o-ring on the underside if not to make it watertight to the "worktop". I do not understand why an additional washer would be necessary, it seems to negate the need for the o-ring.

Having read many of your posts, I appreciate that you know more about plumbing than me. If I see advice that I do not understands I will question it. Again, no offence intended.

No apology necessary, probably me just being defensive. I get what you’re saying, no additional washer should be required, it was more to “help” the OP. Clearly some of this stuff on the market is being sold without any sort of design criteria as per @Scally-Ho.

 

[Madrab]

Yeahaaa - 29 posts for fitting a tap lol

The hand nut with the brass thread should be able to go tight enough to allow the tap to be secured properly so it doesn't move. If it is moving then it can only be certain things. It's not tight enough, the o ring isn't large enough and isn't gripping properly or the surface or the o ring is slidy allowing the tap to move. Any tap on a ceramic sink shouldn't be overtightened, as it can damage/crack the ceramic.

I'd take the o ring out and clean it all up and the seals for underneath and underneath the sink itself and try again. If it still moves then time for a little silicone adhesive (not sealant).