Shift button coming loose on the Schlumpf Speed Drive

Dear Bietrume,

might it be possible that the small Allen screw is of the wrong length?
It should be 5 mm.
(Maybe you could use a longer screw i.e. M3x6 or M3x8 mm)

Are you sure that the button is adjusted correct?
The surface of the button should be (when engaged) plain with the surface of the cranks.

The right one is a little bit too much outboard.

Right:

Left:

(The installing instructions were moved from the above mentioned topic to here.)

(From the Manual-Sclumpf-Speed-Drive.pdf (17,7Mb), Chapter B-5, found here:
http://www.haberstock-mobility.com/en/products/schlumpf-drive/schlumpf-speed-drive.html)

*[a pair of pliers]
That’s meant for the old non-slotted version of gear shift buttons (before October 2004).
Instead of the pair of pliers please use the special wrench (tool B of
this post).