Originally Posted by noisebeam

Wow. We are so much on the same page. Last time I was messing with it, I tried reversing the bolt for the same reason - but then you can't tighten the wing nut as it interferes with the plastic housing (it could be replaced with a regular nut - come to think of it I have one as I replaced it with a washer (the oversized nut))
As to the plastic - I'm thinking on the same lines, but instead of the three stacked washers a thick rubber washer - it would have more friction (when dry), but more importantly, the movement from a road shock would be absorbed by the rubber instead of slipping, then it would stay in place as it would 'bounce' back in place.

Al