You're not taking the cables off the bracket, right? There's no need to do that unless something else is wrong.
On the bracket, there's a couple holes that will line up so you can stick a philips screwdriver in and the valve won't turn. Take the nut off first (it's reverse thread which may have had you messed up). Note where the washers go so you can put them back in the correct order. Then take the 2 attaching bolts out (normal thread) and the whole assembly comes off the cylinder.
Usually you don't have to jam the bracket with a screwdriver but if you've been trying to turn the nut the wrong way it might be on super tight now.
Last edited by craigsutton on Mon Apr 12, 2010 12:49 pm; edited 1 time in total