One of mine did the same thing. I was able to put a socket on my drill and after i had all the other bolts out i just kept reversing the drill and pulling gently on the cover...the nut will get hot from spinning in the inner cover and melt the plastic just enough that you can get the whole thing to pull through the inner cover. Once it was out i had to cut the nut off the bolt because it was froze to the bolt, cut the head off the bolt and kept the little alignment washer and slid it over a regular bolt that i got from the hardware store...the new bolt is long enough that it sticks all the way through both covers and i placed a flat washer and teflon lock nut on the back side (engine side) of the inner cover. Was really easy after i figured out how to get the thing apart.