Need a fix for my HE-4xx

the left arm adjustment post doesn’t hold position when I move it…it slowly slides all the way back to the bottom. that didn’t bug me at first, but I realize now that I would appreciate a little more height now. it’s not quite uncomfortable but in time I see that I would likely benefit.

Could try adding some kepton tape to the slider to increase thickness.
Apply it in such a way that it runs upwards and do not wrap the slider (that will end up making a mess).

You’d need some sort of dilatant, essentially thickening lubricant. Colloidal silica would work but you’d have to make it yourself, since I don’t know anywhere that sells it as a suspension. It’s normally used as an additive for waterproofing. It’s cheap stuff so you can experiment with different mediums (water, oil, maybe even silicon grease if you used a lot of silica) to see what works.

Zeos would say “blue tack it”