Overhauling Heater/AC Box
Back to the fiberglass box...
There is a hanger that suspends the box near the passenger side kick panel. It connects to the fiberglass heater box through a hole with a screw in it. The fiberglass in that area had fatigued and cracked so that it was all jacked out of shape.
I C-clamped a piece of 1/8" steel plate to the outside surface of the box and tightened down on it to pull the surface back to as near flat as it would go.
I put a propane torch to the steel plate to help relieve the fiberglass and hoped that it would conform to the flat shape. It seems to have worked out well. Once it cooled and sat for a few days, I applied super glue to both sides of the fiberglass. So far, it has held in place. We'll have to wait and see how it does after it's re-mounted in the car.