I started the rebuild of the damaged front vent. I chucked a 9/64" bit in the drill in order to remove the rivets holding the vent together. I worked from the peened side and carefully used the drill to cut away the rivet. I stopped drilling while the rivet was still intact in order to keep the bit from enlarging the holes in the cover pieces. Once the rivet shank was almost gone I used a drift punch and mallet to drive the rest of the rivet out of the cover. Once the rivets were all removed the vent pieces could be separated. This also freed up the ratty old gasket.