unscrew the nut under the sink and then you can turn the lever counter clockwise, sometimes there is plumbers putty that makes it hard to unscrew the lever without taking the nut under the sink off, watch this link
https://www.youtube.com/watch?v=zc7Q5666yoU
Answer from user111874 on Stack ExchangeVideos
How to replace valve cartridge on Kohler DevonshireWidespread bathroom sink faucet - Home Improvement Stack Exchange
How to remove this Kohler single handle faucet cartridge?
How Do I Remove This Kohler Single Handle Faucet Cartridge??
Kohler kitchen faucet cartridge replacement issue
Kohler sucks. They make everything harder than it should be. Fuck them. Take your free new faucet as payment for owning a faucet that’s next to impossible to service.
More on reddit.comunscrew the nut under the sink and then you can turn the lever counter clockwise, sometimes there is plumbers putty that makes it hard to unscrew the lever without taking the nut under the sink off, watch this link
https://www.youtube.com/watch?v=zc7Q5666yoU
Give Kohler a call. All their products carry a lifetime warranty or at least they used to, They can explain the procedure you are looking for and send you the repair parts free to you.
I have a replacement cartridge for this Kohler bathroom sink single handle faucet. The Kohler support line when I ordered the warranty replacement cartridge insisted that no special tools were needed to unscrew the old cartridge.
But as far as I can tell, it is held in by the metal ring to the outside of the red plastic ring. The metal ring has flat sides but I see no way of getting a grip on it without some sort of special tool.
Do I need some sort of special socket tool to unscrew this?
I can’t figure out how to remove this cartridge. It’s an older Kohler, single handle kitchen faucet. Do I need a special tool?