by Art Gardner
My wife and daughter were following me home in my 6107 one night and reported that one of my tail lights was brighter than the other. At first I disbelieved them, but then thought they must be looking at one of the lights from not quite straight on. As you know, the tail light lenses have a focuser in the middle that creates a rearward beam, so I figured they each thought the one in front of them was brighter. However, checking myself I found they were correct: the left light was brighter. Switching the lenses from one side to the other didn’t help and I then noticed the bulb filament on the left lamp was lined up with the center of the focuser part of the lens, while the bulb filament on the right lamp was positioned noticeably below the focuser. As a result the focuser on the left lamp was getting a stronger dose of light than the right one.
Anyone run into this before? For the life of me, I couldn’t think of how you would adjust the position of the bulb relative to the lens…… Well, I think I have the answer. It appears the mounting boss into which the tail light socket is mounted is positioned below the “beam focuser” part of the tail light lens. To position the lamp at the level of the focuser, the factory made the mounting flanges on the sides of the sockets to be not perpendicular to the sockets, but canted at an angle. This points the bulb upward such that the filament is lined up vertically with the beam focuser. When I restored the housings, I must have installed the right side socket upside down, so that it points slightly down instead of slightly up. That caused the filament to be well below the level of the beam focuser, such that not as much light was traveling straight back through the beam focuser portion of the lens. I switched this around by undoing the two screws that secure the socket and twisting the socket 180 degrees. Now it lines up correctly. Here is a schematic drawing (exaggerated a little and not to scale) of what I am talking about. The moral of the story is that it appears that there is a correct orientation for installing the sockets (and an incorrect one).
BULB AND SOCKET MOUNTING FLANGE IS SECURED IN THE BOSS WITH 2 SCREWS
