There's a sheet stuck under the agitator on this machine. I've removed the cap of the agitator by unscrewing it. There's a stud under it with a 5/8" hex bolt in a very tight space. Is there a special wrench to unscrew this? I have a 5/8" socket but I doubt if it will fit over the bolt because it is inset.

Are you sure it's 5/8? All I've ever seen were 7/16 and with an entention on it, easy to remove

I measured it and it's 5/8", surrounded by a six-sided opening of 3/4", so there's very little space to fit a socket into.