How to replace worn seat in sink taps?

[Krusty]

G,day spanner turners my bathroom taps have been over reamed and I can’t seem to explain to Bunnings staff the name of needed part,spindle and washers are all fine it’s the seat inside the tap that’s worn,have tried replacement sleeves these don’t work in this instance,please help kids are sick of brushing their teeth in the kitchen,cheers Krusty.

[Krusty]

Thanks Mitchell this community has been more than helpful Red has me sold,heading to Bunnings,Krusty.

[DIY-Dilatante]

This appears to be almost identical to my situation, save that my connecting Tee is straight rather than curved (and a little longer).

However my proposed solution is rather different: I would like to install a mixer like the https://www.bunnings.com.au/mondella-wels-4-star-7-5l-min-35mm-cadenza-cast-basin-mixer_p5003310

However I'm concerned that a mixer has (at least) 2 incoming pipes, and so maybe needs a larger hole. I'm guessing from my photo that the spout is screwed down onto a ½inch thread, which would imply that the hole is at least 17mm, but I cannot see the hole until it's disassembled.

The installation guide https://delivery.bunningscontenthub.bunnings.com.au/api/public/content/bc377a838db34574b0e7f733f2e48... does not mention the size of hole that should be cut.

Any guidance on either (a) expanding the hole in the sinktop, or (b) identifying which mixers might fit, would be appreciated.

[redracer01]

Hello @DIY-Dilatante 

Welcome to Bunnings Workshop. The hole size you are after is 30mm to a maximum of 32 mm but no bigger than that. Most modern basin mixers have a base size of 35mm some with extra base flanges that extend it out to 40 mm, but as a rule of thumb you never drill bigger than the base of the tap. Converting from traditional hot and cold to a modern single mixer is a time honored practice. Specially if the vanity is still in very good condition. I always recommend to put in isolation taps so that you can isolate the basin mixer without having to turn off the plumbing in the whole house. 

Drilling through acrylic : Good quality hole saw. Watch lots of video guides before attempting.

Drilling through ceramic : Danger level extremely high, possibility of cracking porcelain also extremely high. I would not recommend it.

Below are the basic items you will need should the hole for the basin mixer be big enough. Good luck and stay safe.

Cheers,

Red

[MitchellMc]

Hi @DIY-Dilatante,

It's great to see you've already received a comprehensive reply from the knowledgeable @redracer01.

You might actually find that the holes for the taps are larger than the spout hole and you could locate your mixer to the left or right and block off the spout and other tap hole. I recently completed a similar project, and I was able to place the mixer through a tap hole. It was tight, but I managed to fit the two small flex pipes and the locking mechanism through easily.

I'd suggest the best place to start would be removing the spout and checking what size hole you have to work with.

Please let us know if you need further assistance or have questions.

Mitchell

[DIY-Dilatante]

Hi @redracer01

Thanks for your reply.

I already have all the items shown, except the pipe cutter and compression unions.

It's not clear to me why I would need those, but perhaps I didn't explain well enough: the taps are currently fed by (braided flexible) hoses, which are visible in the foreground of my picture; the only rigid pipework is the mixing junction between the taps, which I intend to remove along with the taps and spout, and the in-wall pipes, which I'm not changing.

I've bought a Mandella Cadenza mixer  (https://www.bunnings.com.au/mondella-wels-4-star-7-5l-min-cadenza-swivel-basin-mixer_p5003380) which has a threaded shaft of about 30mm and a base of about 50mm, but the O ring underneath is set in by a few millimetres and that would be the limit for how large a hole I could drill. (That said, if the hole is large and slack, the tap could slide so far off-centre that the O ring won't seal, so I will use the smallest cutter I have available.)

When I've drilled using a hole saw before, it has had a long guide bit in the centre, which obviously won't help if I'm expanding an existing hole; so am I likely to encounter any problem with "drifting"? (I don't want to wind up with scratches on top of the bench around the hole; even if they're not visible, they may compromise the O-ring seal.) I'm using a battery-power drill/driver, so "take it slow to start" is obvious, but is there anything else I should do to counteract drift when starting the hole?

I will use a rasp to check whether the basin is ceramic before drilling.

Incidentally, cut-off valves (aka mini cistern stops) are available in 2-packs for $12, which is 19% cheaper than singly.

[DIY-Dilatante]

Hi @MitchellMc 

That's ordinarily a good idea, but my options in this case are firmly limited by "other people's aesthetic preferences", so expanding the centre hole it will have to be.

Your approach would also be useful for a traditional configuration with 2 separate taps without a mixing nozzle.

[redracer01]

Hello @DIY-Dilatante 

My apologies for not looking at the photo clearly. You won't need the compression fittings or the pipe cutter. When assembling the basin mixer just remember not to forget the o ring for the bottom of the tap. From the bottom end of the vanity the rubber goes first before the steel halfmoon washer then the last will be the nut. Tight enough that it's firm but not overly that it bends the washer. The base of the tap must be centered to the hole so that the rubber grips the vanity top and not slide around. The rubber at the bottom grips the underside of vanity and prevents the washer from sliding around. Goodluck and stay safe. 

As for the drifting you can temporarily wedge or fix a piece of timber under the old tap hole. You can screw it to the wall temporarily. Put a pilot hole dead center of the old tap hole. Now assuming your using a drill guide for your hole saw you should not have any trouble drilling center.

Cheers,

Red