Thanks for the help. I discovered that the Cobra IS the same as the '96 and '98, but the tension of the metal clip against the shaft was very strong on the Cobra...I just couldn't get it to release. Ultimately the clip separated from the plastic knob, and I removed the clip all by itself. Then, I used epoxy to join it back up with the knob. Before doing that I bent the clip a little, so that it wouldn't be so tight if I get the pleasure of cleaning the dirt out of my instrument display again sometime.

By the way I slipped an o-ring over the shaft of the odometer reset button to plug up the open space between it and the cluster face. Hopefully that will prevent some of the dust from slipping in there. I've had 3 convertibles, and a dusty instrument cluster is a standard problem. Thanks again!
