You can get to the antenna mast base without completly removing the fender. With the fasteners you mentioned in your first post removed, you can flex the fender back far enough to get to the bolts holding the antenna base to the chassis. Remember, the fender is plastic and will tolerate a fair amount of flexing. If you take the wheel well liner out, it makes it easier to get to the grommet where the antenna cable goes into the interior. If you still want to take the fender off completly, the ground effects do not need to come off. The rocker panel should be removed to get to a large single rivet that holds the bottom corner of the fender to the frame, although it may be possible to just take out the first 3 or 4 rivets holding the bottom of the rocker panel to the frame and flex the front end down far enough to get to the fender rivet. The rivets can be replaced with screws and nuts if desired.
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Rod Schneider, Woodstock, Ga.
"You can't have too many toys!"
1988 Fiero GT
1966 Porsche 911
Van's RV-6 airplane-under construction