On Mon, 26 Apr 2010 16:45:27 -0700, "Steve B"
wrote:

I got a used Motor Guide Brute.. Where the SS (?) chromed shaft goes
through the aluminum clamp, it is firmly in there. I cannot get it to
twist. (Yes, yeah, I did loosen the nuts.) I put some sewing machine oil
on there and left it to flow vertically. Is PB Blaster better? Should I
put a pipe wrench on it? Waiting for it to move on its own rather than
brutalizing it. IT doesn't appear, even with dissimilar metals that there
is any galling, and this is a freshwater application.

PB Blaster is good and available everywhere.

Aero Kroil is better but must be ordered on the web.

Supposedly best of all, but I haven't yet tried it, is a 50/50 mixture
of acetone and transmission fluid. Acetone is highly flammable of
course.

With all the above, apply, tap lightly with a small hammer, wait,
repeat.

When all else fails try carefully heating the aluminum with a propane
torch.