potentially stupid newbie post #2, on luggage rack install

[manlio]

Ok, so I bought a used luggage rack and system cases for my 2004 Rockster (they are the same as the classic R 1150 and mount in the same way).

I assume bolting on the rack would be fairly simple, but I didn't even get to find that out. The plastic pieces that cover the rear threaded holes to secure the rack in the back are easily removed.
However I was not able to remove those black "things" from the spot where the rack has to be bolted in for the front. They are not simple plastic push-in caps, as I thought. They do not screw out, as I tried to do with a plier from the other side, and the plier seemed to damage the little tip pointing inside. I tried to push it out by hammering. I inserted a blade between the metal part (hosting the nut) and the plastic but nothing other than scratches.

I don't have a clue as how to remove the damn thing. Even breaking it away seems to be quite difficult as you have to work from the other side between the tire and the seat.


Any obvious solutions that I am too blind to see?
Your help is much appreciated.

thanks a lot, ride safe

Manlio