Concealed shower shut-off knob stuck fast

[Jonnie]

Hi. Just joined the forum in the hope of some help removing a shower knob. I have an Axor Starck concealed shower (picture attached) and have been trying remove the shut-off knob for some days now. The thermostat knob below it came off quite easily. I need access the cartridge to fix a persistent dripping from the shower head.

I have removed the grub screw located under the knob but the knob will not come off. I have been trying penetrating oil in the grub hole but at best the hole only moves to the horizontal ( it’s a quarter turn shut-off) so getting any oil to stay in is problematic. I’ve tried hitting it with a hammer through cloth, using hot water to expand it, and gentle prizing just wrecks the chrome finish on the knob and the sleeve behind it. I’ve read about handle pullers but can’t see how this would work on this design. I’m all out of ideas. I’d even consider replacing it completely but this one still has to come off somehow!

Any suggestions please?

Thanks.

 

[Ben-gee]

It does ‘just’ pull off.
To let you know, in the past I have had to cut them off.
When fitting the replacement, put some silicone grease on the splines to facilitate easier future removal. If you can be bothered , remove/replace annually - the shower itself will likely last in excess of 20 years, 26 is the oldest on my books, recently had a new thermostatic cartridge.

 

[Jonnie]

It does ‘just’ pull off.
To let you know, in the past I have had to cut them off.
When fitting the replacement, put some silicone grease on the splines to facilitate easier future removal. If you can be bothered , remove/replace annually - the shower itself will likely last in excess of 20 years, 26 is the oldest on my books, recently had a new thermostatic cartridge.

Many thanks Ben-gee for you quick reply. I’m reluctant to use much force for fear of damaging something inside other than the knob itself which I can replace. Will the spline and other components stand a reasonable amount of force?

In the event of having to cut it off, I’m assuming the knob is brass so would a hacksaw do the job and where is the best place to attack it?

Yes the shower has done excellent service - apart from this one item!