Pop-up bath waste - can't remove control knob

[minimoog]

Dumb noob alert - I need to remove and re-fit my bath overflow and pop-up control as it's become loose in the hole. Unfortunately try as I might I cannot get the big chrome control knob off. It doesn't have a grub screw so I assume it's just a push fit - but it will not budge.

I'm wary of cracking the bath so before I go further (I'm thinking a hub puller and some kind of timber jig to hold it over the damn thing and push against and spread the stress) is there any chance at all this could be attached from the back? Or are these knobs all either grubscrew or pop-on/off?

Thanks.

btw I'm not sure what make/model it is but it looks very like this Crosswater one

https://www.crosswater.co.uk/product/bath-pop-up-waste

 

[oldbutnotdead]

Horrible things, very sensitive to the way the cable runs.
Does the front not pop off that knob (looks like 2 parts). Low odds you'll be able to tighten it in its hole from the front anyway, you'll prob have to get behind it

 

[Harry Bloomfield]

Does the operating rod not release from the mechanism below? Knob and rod come out as one part? Mine do!

Look for a long threaded nut, which joints the rod to the rest of the mechanism.

 

[Madrab]

Twist the knob round, you'll probably see a hole in the side of it, there should be a screw or grub screw in there that's holding it onto the spindle.

 

[picasso]

If there is no hole on the chrome knob its just a pushfit, try and get your fingers behind it on both sides and give it a good yank.

 

[minimoog]

Definitely no grubscrew.

The damn thing still will not shift. Cant get a purchase on it with a wrench. I've tried prising it off with a chisel, then tried hitting the chisel with a hammer when that didn't work. It's moved a few mm perhaps but the hammer just produced cracking noises which made me think the bath panel will give way before the knob does.

W

hat a **** of thing

 

[picasso]

Can you post a pic of the bottom of the ****ting thing ?

 

[JimCrow]

Pour some boiling water over it then try again while it's still hot.

 

[Alec_t]

If the waste is indeed like the one in the link then this disassembled view suggests there could be a circlip holding the knob in place? Or else it unscrews if it and the plastic part behind it are rotated anticlockwise far enough?

 

[minimoog]

I'll give the hot water idea a go, might as well add a scald to the chisel slash across my wrist

After that it's either a hub puller jerry-rigged somehow or try and get in behind with a padsaw and hack the thing to bits and replace with new.

Can you post a pic of the bottom of the ****ting thing ?

You mean like this? There really isn't a grub screw, if that's what you're thinking.

 

[minimoog]

If the waste is indeed like the one in the link then this disassembled view suggests there could be a circlip holding the knob in place? Or else it unscrews if it and the plastic part behind it are rotated anticlockwise far enough?

Hmm if I zoom in on that I'm not seeing a circlip. A small O ring maybe. It looks like the knob just pushes onto that square section shaft on which there's a couple of protruding tabs that secures it.

I guess I'm just not being aggressive enough with it, but I really don't wanna crack my tub...

 

[picasso]

Put the chisel between the chrome knob and its back plate and lever it off.

 

[minimoog]

Put the chisel between the chrome knob and its back plate and lever it off.

Obvious now you say it. Will try tomorrow.

Thanks.

 

[Marley13]

@minimoog
Did you manage to remove the knob ? We have the same, plug is stuck in bath, knob is extremely tight but the lining is also coming away ‍ Can’t seem to prize the knob away

 

[Burnsy16]

I've just removed one of these. You need to remove the cable from the unit and then the front will unscrew.