I’ve got some continental protection mountain king 2s which I’ve recently set up tubeless. The front was okay but the back is really leaky on the sidewalls. I’ve cleaned the inside of the tyre to get rid of any release agent.

There are a few visible spots where the sealant is leaking through but if I put the tyre in water I can see that the whole sidewall is losing air, as if the sidewall is porous rather than just having a few holes in it.

I’ve put 3 small bottles of sealant in it, ridden it, shaken it up, left it lying on it’s side for 2 weeks now and it doesn’t seem to be any better. I can put 40psi in it and an hour later it’s completely flat.

I opened it up and there was a big ball of congealed rubber bits rolling around in the liquid sealant, does this mean the sealant is knackered?

Has anyone had any luck with the homebrew sealant I’ve seen mentioned on mtbr? They talk about mixing model making latex with ‘windscreen washer solvent’, is that normal car windscreen washer fluid or something different? How about just painting the latex onto the inside of the sidewall?

Or do I just need to buy a gallon of proper sealant and start again.