Stiff Tap Cartridge

[Rubato]

Having removed the cartridge and lubricated with plumber's grease it was still stiff. Removed again and sprayed with silicone aerosol and just as stiff. What I notice is that it turns well when out of the tap but becomes stiff when installed. It is only 3 years old and no signs of wear ( kitchen sink ). Thoughts ? https://www.tapmagician.co.uk/NSManufacturersShoppingSelect.aspx?NPT-Q148J

 

[oldbuffer]

1. The silicone rubber washer at the base of the tap compresses when installed to provide a seal. This tightening may be what is causing the tap to become stiff.
2. Are you sure the seating depth of the insert you have is correct?
3. You could try installing it then backing off by 1/2 turn. If this allows it to turn freely, it suggests the sealing depth should be 22 mm rather than 23 mm. Note, you can't use it backed off, you'd have to change the insert.

 

[Rubato]

I installed the cartridge 3 years ago and has gradually become stiff. It's not installed tight. This guy uses WD40. Think I'd rather order a new cartridge!