I have a single lever mixer tap which needs a cartridge replacement. I’ve managed to open the lever using an Allen key. This brass nut has had me stumped. I don’t want to use a tap wrench and damage the nut.


  • What brand is the faucet? A simple Google search for faucet cartridge remover for <brand> would likely show you exactly what you need. Commented Mar 2, 2020 at 20:08
  • Unfortunately I’m unable to locate the brand
    – adarshr
    Commented Mar 2, 2020 at 20:31
  • 2
    @adarshr get a small mirror and look at the base of the faucet between the faucet and the wall. Sometimes they print the name brand on the back.
    – JPhi1618
    Commented Mar 2, 2020 at 20:33

2 Answers 2


There are a number of spanner wrenches that you can use. If you're replacing the cartridge, you can probably pick up a cheap wrench where you purchased the cartridge or at a plumbing supply store.

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I usually just get a piece of bar stock and place the end in the groove and gently tap it with a hammer ccw.


In addition to the excellent post from JACK above, your local hardware store should carry an adjustable pin wrench (also known as an adjustable angle grinder pin spanner). This usually goes for around $10 from Trade Tools, Total Tools, etc. and can cover a range of typical pin style cartridge locking nuts.

Alternatively, measure the thickness of the gap in the two cutouts, then find a suitably thick piece of aluminium, brass, steel, etc. and cut a shallow U-shape (low enough to fill the indents but high enough to clear the cartridge) out of it with a grinder or hacksaw. Put the U shaped spanner into the cut outs, then unscrew the locking nut with a shifter, applying firm, gradual pressure for consistent torque until the locking nut loosens. Applying sharp pressure may free it up if it is stuck due to age/build-up but may also bend your custom tap spanner.

I have also had limited success with a pair of long nosed pliers and a significant amount of downward force and grip but I would not recommend it where any other option is available.

As always, use a licenced plumber in accordance with local legislation when working on plumbing and if the mixer is older than 5-10 years you should also consider replacing the braided hoses, especially if they the stainless steel type if you have chemicals stored in the cabinet under the mixer. Most mixer tails have an M10 fitting for the mixer and a 1/2" BSP wall fitting and the standard length is around 300mm.

As an aside, if your cartridge locking nut is a recessed hex nut type and your spanner, sockets and screwdriver will not fit, use a pressed steel tube tap spanner set with torsion bar from Bunnings.

In addition to what JPhi1618 said, if you can't see the brand anywhere on the mixer, look up the WaterMark licence number on the back which can be Googled to see who the manufacturer is. It will look like LN0202 for an old mixer or something like WMKA02020 for a more recent mixer. Sometimes multiple brands use white label product from the same factory, and some manufacturers are no longer operating, so this may not be clear cut.

The above is my personal observation/opinion and may not be appropriate for you.

  • 1
    I'd guess that things like looking up the "WaterMark license number" and "Bunnings" will only apply to those in Australia. ;)
    – FreeMan
    Commented Apr 22, 2022 at 11:05
  • A selection of the cheap stamped steel wrenches that are sometimes provided with various tools or bicycles or automobiles may yield an open-ended stamped steel that will already have a cutout in the center and fit in the slots, and then you can apply an adjustable wrench to that to apply turning force.
    – Ecnerwal
    Commented Apr 22, 2022 at 11:34

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