Thanks. So were there two shims on top of each other between the white cog and the link to the axle-teeth? Iirc one is wavey, so has kind of a spring function, the other is just a plain and simple shim. And the one I put into the last pic of my previous pic, lying on top of the white cog is indeed in teh correct position?
If the white wheel received some more damage, it sounds like the friction is indeed in the axle.
One of the pics that failed to upload. You can see the metal on the axle is somewhat darker where the o-ring sits. The o-ring is shown on the left, with the plastic cover that pushes it in place. This darker patch is where the crevice corrosion is. Last time it also had quite some rust on the axle itself. You did sandpaper this to a smooth finish if you had that too?