Those are bronze, their purpose is to prevent the aluminum casting from getting chewed up.
I'm betting that you'll find two tapped holes and one through hole on the compressor.
If I'm remembering right, the two bottom screws were easy - you might be able to use the allen wrench, with a socket/extension over the free end, for leverage. The difficult one is on top, you can either use the allen wrench, as shown in my link, or a long enough bit may get you out beyond the back of the compressor case.
Look forward to hearing how this turns out, I'm optimistic. |