Mirror stop adjustment on Minolta XD-7 /XD-11

[retinax]

I've realized that the mirror stop and thus the focusing on the otherwise working XD I finally got has gone way out, thanks to the rubber sleeve that's on the little post having deformed. I have studied the service manual but not found how to adjust it.
The post itself is a screw that would require a flathead screwdriver or rather, two, bent 90° to access it. Does it need to be unscrewed?
What material would I use to replace the rubber sleeve with? Any specific material of tubing that would hold its shape well? What's in there now is not cracked or something, but I'm afraid it will further deform over time.

 

[B-9]

Heat shrink tubing? Cheap and custom fit with heat!

 

[retinax]

Heat shrink tubing? Cheap and custom fit with heat!

Yes I was thinking about that, but wondering if there's a tried and proven solution.

 

[retinax]

For the record: Turning the post itself does the adjustment, it's eccentric. However it doesn't move enough to compensate for the worn out rubber sleeve. I guess I'll try heat shrink tube, hope it will hold up.

 

[retinax]

Update:
There of course are screws for adjusting the focusing screen position. No idea why I couldn't find them the first time around. JIS cross heads, placed where you'd expect them, around the prism.The heat shrink tube did work well enough though, but I wasn't sure how it would hold up, which is why I investigated again. Now to get the top plate back on... bit of a pain with this camera.