Something similar to what the OP reports happened to me yesterday. I've misplaced the cylinder that stabilizes the spacebar.
I've ended up making one from scratch using a credit card, a paper clip and a Bic Cristal ballpoint pen. It fits snugly on the cross hole of the key and the space bar is not wobbly anymore.
This is an oldish post and I'm short on time, so the gist is:
- Cut a thin rectangle of the credit card (0.5 cm x 1.1 cm). That should fit in the horizontal part of the cross hole on the key.
- Cut two straight segments of the paperclip and push them onto the upper and lower parts of the cross hole. I've used a color paperclip, and stripped the plastic of the part that fits in the hole and left it on the part that sticks out.
- Take the tip of the bic cristall pen (the brown part) and cut a 0.6 cm section of the cylinder that is normally hidden inside the pen.
- Push that cylinder around the credit card+paperclip column. In my case, it doesn't move once in place, but if it does I'm sure you can add some extra filling.
If the above instructions are not clear and there's somebody out there still missing their AEK II cylinder, I'll post pictures to clarify them.