Removing antenna from open array

[Mountain Boy at Sea]

Chuck,
I have the same issue, except that I have been unable to even take the 2007 analog radar off the hard top, and can't enjoy my new one. It appears that unless I can remove the antenna arm, I cannot access the screws that attach the pedestal to the SeaView radar and TV mount. So, like Bill, after removing washer and nuts, I can't lift the arm off the pedestal.

Getting these 4 screws loose has become an unsuccessful obsession. I have soaked with 6-56 etc, but it looks like they are fused to the support, and gentle hammering with a rubber mallet has not produced the desired result.

What's the next less gentle method (physical or chemical), also considering that I don't have a lot of space to work with up there? Any help or advice welcome!