Check with your local fire department and see if you are in a high strike area, and yes they do exist. If you are not in a high strike area the normal code grounding should be sufficient.
Don't take the Pan/flywheel off unless it is bent, it weighs around 50lb an most likely will have to be heated. On mine I put the 3/4 socket in the hole and then work it over the nut then add the extension.
I can see the nut in your picture and it looks ok, I don't understand why socket wont...
Take a cut off grinder and enlarge the hole to get to the bolt. If you cain't break them loose borrow or buy a 3/4 inch $69.99 SAE or metric Search Results For "3/4 In Socket And Rachet Set" Use a pipe for extension handle. Don't try to change the Pan/Flywheel unless it is bent, you have to...