ClassicCar

You may not have the screw backed out far enough. Try removing it (the screw on my Terraplane is "stepped" -- it has an upper and lower thread, separated by an unthreaded portion. You unscrew until it drops down maybe 1/2 inch -- this indicates the upper portion no longer holds the lens retainer. Then you continue to unscrew and the screw itself drops out.



The whole thing may be corroded and thus requires a bit of light "thumping" with the heel of your hand, around the perimeter of the glass to loosen it. Remember to put pillows and blankets in strategic locations under the lens, to catch it if it falls out.



The setup is pretty simple. There is the lens, then behind it is the brass (silver plated) reflector with socket and lamp. This has a round cork gasket that contacts the back of the lens and may be sticking to it (which is why it's hard to move). There are three clips around the perimeter of the shell (they "slot" into the shell), holding the reflector: one each at the 10 o'clock and 2 o'clock positions, and a rather involved one at the 6 o'clock position. On the ack of the reflector are three simple brackets that fit into the three spring clips. The reflector-riveted bracket at six o'clock has a hole in it which is captured by the securing screw. The screw passes through the six o'clock spring clip (attached to the shell) and into the hole on the reflector-mounted bracket. When the screw is in the hole, the reflector (and lens) can't move inward.



So, either that screw is still holding the reflector bracket at six o'clock, or the lens has become bonded to the reflector's cork gasket (no play between the reflector and lens, means it's hard to separate the two).

As you turn the screw try alternately pressing and not pressing on the lens (to ease the lateral stress on the screw). You might possibly try twisting the lens to see if that may help the situation. In fact, if you can obtain a large suction cup with enough of a curvature to it, you could use that to help pull on the lens when you're ready to remove it. A suction cup tool was used originally by Hudson servicemen to remove the lens.



You may want to use a thread chaser to restore the threads in the headlight shell, once you've removed the screw and the inside of the lens.



When you're inside the headlight you will want to inspect the silvering on the reflector and had that re-done if it warrants doing. You might also want to solder dedicated "ground wires" to the socket itself, and run them to a ground somewhere on the frame. There may be enough rust on the various brackets and bolts holding the headlight, to where a good ground is no longer made.