How to tighten a mixer locknut?

[kgdoctor]

Hi.

I am seeking help here to find the right tool or right way to tighten the mixer locknut. Now it gets loose and water can leak through into the cabinet. The size of the lock nut is 40mm and I have tried the adjustable wrench but due to the constraint space around the lock nut, it was impossible to put the wrench in and turn. I can do the hand tight but it gets loose every time I swing the shower head between sinks. I guess there must be a special tool I can possibly buy for this purpose. Please help if you know the answer. Thanks a lot!!!

 

[MitchellMc]

Welcome to the Bunnings Workshop community @kgdoctor. It's brilliant to have you join us, and many thanks for your question about installing a sink mixer.

I can see that tightening the nut in such a confined space would be difficult. There is a good chance you'll be able to use a basin wrench to access the nut and tighten it. The head of the wrench tilts over to 90 degrees, and you use the T-shaped handle to turn the nut.

Please let me know if you have any questions.

Mitchell

[kgdoctor]

Thanks Mitchell. @MitchellMc 
I thought about it before maybe give it a go. Would you be able to help me to check if it is big enough for the 40mm nut? Measurement is between the outside parallel faces as “S” is the photo below. 

 

[MitchellMc · Accepted solution]

Hi @kgdoctor,

Basin wrenches are typically designed for nuts up to 25mm. However, you might be able to tighten your 40mm nut if you can manage to catch a corner with the teeth.

The other method you can try that I often employ is to hold the nut in position and tighten the fitting using the mixer body. Start by turning the mixer to the three o'clock position. Tighten the nut up by hand. Try and jamb some timber or a screwdriver between the wall or the sink basin and a flat side of the nut. You want to try and hold it in position as much as possible. Even a second person holding the nut by hand might work. Then, rotate the mixer back to the six o'clock position. If, through this method, you can tighten the locking nut enough that it holds whilst the mixer is being swivelled in normal operation, then you might have a solution. I've used this method numerous times with success.

It's a bit hard to tell how much room you have between the sink basins and wall, but you might be able to get a small strap wrench or slip joint pliers up in there. If so, you could possibly tighten the nut bit by bit with tiny adjustments.

Let me mention one of our knowledgeable members @TedBear, who might have some ideas.

Mitchell

[TedBear]

Hi @kgdoctor , further to @MitchellMc s suggestions, perhaps a multi grip plier such as these will get you there....

@ https://www.bunnings.com.au/trojan-250mm-multigrip-plier_p01269 .

However, I am confused by the picture of the locknut. It appears to have a gap in it....  is that so, or just an illusion? I have never seen a locknut like that before and I wonder how it can ever be tightened, since it appears that it would open up and release under strain.

[TedBear]

Hi again @kgdoctor,

you mentioned that water gets through into the bottom of the cabinet.

Looking more closely at the picture of your installation, although it's hard to be sure from a photograph, I can't see both washers under the sink - the rubber seal and the "fixing plate" between the sink and the locking nut.

Are they both there?

The fixing plate should prevent the locking nut from digging into the rubber seal, which would result in it being stopped by friction (and distorting the seal) before it gets to fully pull up and compress the top and bottom seals into place.

[kgdoctor]

Hi @MitchellMc 

thanks for the further advice. I did the research before and if I remember correctly, the basin wrenches is not designed to fit for 40mm-ish lock nut so reluctant to try out and safe the trip to return the product. 

I just followed your idea to get the adjustable spanner fully open and jammed it between the nut and the basin wall and did exactly what you posted up there. And guess what. It workssss.... save 150 dollars to call out the expensive plumber. Thanks a lot!!!

I guess the strap wrench and slip joint pliers may also work if it is the single basin with enough space for the tool to operate. In my case, with the flex tubes, wooden layer divider etc. all in the confined space, those tools will not work. But of course, it varies from case to case. 

[kgdoctor]

Hi @TedBear ,

THANKS for the suggestion. it is the actual nut in the photo. I dont understand either why it is designed to be an opening there. and I reckon it is a bad design as I checkED out the nowadays ones in Bunnings the locknut is the flexible plastic tube shape which can be tighten by hand I guess  

[kgdoctor]

Hi @TedBear ,

good observation. the second washer is not installed somehow 7 years ago by the plumber as I just found out. I guess either got missed or installed wrongly by the plumber. The leaking is caused by the loose lock nut which is turned together with the mixer body (which is not supposed to be) due to the scale build up in between and increase the friction. 

but you are right, if the fixing plate is in place, it may prolong what just happened (loose nut). 

[RSS]

I imagine the gap in the nut is to allow for the hoses to be inserted into the nut.  Maybe the second hose connector would not fit through the nut center with one hose already inserted.

👍RSS.