How to fix leaking mixer tap?

[andyyu]

Hi Guys,

I have a single mixer tap in my bathroom, it was leaking water and I have replaced a new cartridge. However, when I turned on the cold water, the tap was still leaking, the hot water was not leaking at all. How can I fix it? Thanks a lot!

[JacobZ]

Hi @andyyu,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

The first thing to check is whether the new cartridge is fully seated. Even a small misalignment can allow cold water to pass through. Turn off the water, remove the handle and cartridge and make sure the rubber seals at the base are clean and sitting in the right spots. Then reinstall the cartridge in the exact orientation as the original.

If the cartridge is seated correctly, the next likely issue is worn internal O-rings or seals in the tap body rather than the cartridge itself. These rubber parts can harden, tear or flatten over time. When that happens, they may still seal against the hot side but not the higher-pressure cold side. Inspect the inside of the tap for any damaged or deteriorated rubber and replace anything that looks worn.

Finally, take a close look inside the tap body for corrosion, cracks or pitting. If the surface where the cartridge sits has been damaged over time, no new cartridge will seal correctly. A torch can help you see inside the housing. If the metal is uneven or corroded, replacing the tap body is usually the only lasting fix.

Run through these steps and let me know what you find. I am happy to assist further if required. If you require further assistance, could you upload some photos of your tap so we can get a better idea of what we're working with?

Let me know how you go.

Jacob

[andyyu]

Hi @JacobZ ,

Thanks a lot for your reply. I think the cartridge is well seated as the nut was quite tight. I attached the photo of the surface, I have no idea if the surface is good enough for sealing. By the way, how can I check the O-ring of the tap body? Do I need tube spanner to fully dismantle the tap body? Thanks a lot!

 

[EricL]

Hello @andyyu 

One way to make sure that the ceramic cartridge is seating properly is to make sure that the two bottom guides line up with the depressions of the tap bottom. You'll notice that the ceramic cartridge that you have has two small protrusions at the bottom these are meant to guide the cartridge and make sure that it is properly lined up. At the bottom of the ceramic cartridge are two O rings, one for the hot and one for the cold inlet just make sure that they are present and that the surface is not damaged.

I propose re-installing the ceramic cartridge and making sure that it is seated properly. If you still get a leak when the cartridge is in the off position it is either the brass seat for the mixer is damaged or the cartridge itself is damaged due to overtightening. My recommendation in this particular instance is to replace the mixer tap as the brass seat can't be repaired. You can try using another new cartridge to test if the cartridge you have now is broken.

In regards to your query about dismantling the body, I don't recommend taking it apart as the repair effort is not worth it. The time, money and effort spent on searching for a compatible O ring body kit are better spent on replacing the entire tap with a new one.   

If you have any other questions we can help with, please let us know.

Eric

[andyyu]

Hi Eric,

Thanks a lot for your advice.