What tool do I need?[IKEA- Dalskar 903.325.27 (part# 124499)]

This is a cross post from IKEA, and I’ve yet to get a good answer. I am posting here to broaden the audience.

Hi. The lever for the mixer on my 10year old sink faucet, Dalskar, is getting harder and harder to turn. After a bit of research, I’ve found the cartridge(the blue part in the photo) maybe able to be replaced.

I am trying to get the cartridge out of the assembly, however, according to the manual, there is a ring that holds it down(see green arrow in diagram), and I don’t know how to remove this ring. The ring is presented in the diagram to have notches, but in my actual faucet, the notches are missing and is a simple ring.

It’s difficult to get a grip of the cartridge, because the cartridge is below the chrome lip, which is indicated to be a separate part. I’ve used friction pads to grip and twist the chrome lip, but it won’t budge.

Does anyone have experience with replacing these cartridges? Is there a tool to remove the ring holding the cartridge?

Thanks in advance for your shared knowledge.

An Ikea Kattskar (installed ~ 2010) faucet in bathroom is dripping, but not sure how to access cartridge for replacement - any tips?

Image Gallery here

Thinking the caps on the end of the handles would have to get pried off, but not sure - any advice appreciated, thanks!

Boring details aside, I need to replace the cartridge in my four-year-old RINGSKÄR kitchen faucet. After a lot of back and forth over email and Twitter, IKEA here in Canada informs me that since they don't carry that faucet anymore the cartridges that were being specially manufactured for it are also no longer being manufactured and are therefore unavailable.

Surely they can't have unique cartridges for every faucet they sell. The ÄLMAREN looks exactly like our RINGSKÄR except the spout is sort of squared off rather than being an arc. I can't see any reason why they would redesign a cartridge for that but I can't get any such information out of them.

They did advise me there is a 10-year warranty on these faucets, but they have also told me they can't replace the faucet or the cartridge, and nothing in their current inventory really appeals to us as a replacement.

It seems crazy that I would have to replace my entire faucet rather than just a simple cartridge. Has anyone had a similar experience and/or any luck finding replacements for this type of cartridge?