Hansgrohe Axor Starck Basin Mixer dripping

[acideraser]

Hansgrohe Axor Starck Basin Mixer (part number 10313000) is dripping water from the spout.

it's has been fitted over 20 years ago and I suspect that cartridge need to be replaced.
The problem is that I do not seem to be able to figure out which cartridge and how to remove the old one.

If I understand correctly I need to remove the 25mm extension in order to get to the shut-off valve (part 94009000 on the drawing below), but I am not sure how to do it as the actual part looks slightly different from extension (no.14) or the handle adaptor (no 4) on the diagram above.

Photo of the actual part is below but it does not have any grooves for he spanner.
What am I missing?



If anyone is familiar with this mixer any advice would be highly appreciated, thank you !

 

[jj4091]

What sort of water heating do you have. If is not a combi boiler then diagnosing which valve is simple enough, turn off water at the stop cock open another cold tap to relieve the pressure then see if the dripping stops. If not then then it is the hot valve leaking. Personally if you can work out how to remove them then I would replace both after 20 years. Unfortunately I cannot help with how to do it. My guess would be the extension comes out with the cartridge but just a guess, the exploded view is not particularly helpful.

 

[acideraser]

It’s cold water tap, but yes if I figure out how to remove them, will replace both.
It’s in the flat we let out so need to fix it for tenants.

Just need know for sure how to remove it safely without messing it up.

 

[acideraser]

anyone with Axor experience ?