Today I tried changing my front valve cover gasket. All was going well until I got to the bolt holding the bracket on that goes over the cover itself. I got the one off to the side off first and then tried to get the bolt with the star pattern next to the fuel injector. I was taking my time and slowly loosening it and then it started to get harder and harder to loosen, to the point where I couldn't loosen it anymore. I found this odd and just decided to throw everything back together to avoid damaging anything. Does anyone know why this would happen? What should I do to remove it next time? Thank you.