DIY repair on an old car, or a nut job

I actually did this back in the early summer (possibly even spring?—I'm not sure now), but I'm just getting around to documenting it...

I drive an early 90s Chrysler LeBaron (Yes, "I drive the Chrysler"—Steely Dan fans will understand that "Glamour Profession" reference) and considering its age it still runs well and doesn't seem to have too many problems. (Wait, let me find some wood to knock on... OK, I'm back.)

A couple years ago the headlight covers stopped working right—they'd close, but wouldn't stay shut, instead falling back to half open. After a short while, they wouldn't even do that. Here's a front view of the car as it normally looks with the headlight covers closed properly...



I went to a local junkyard and pulled an old headlight cover motor out of a junker...



I got lucky in that the proprietor was in a good mood, I guess, and let me have it for free since he said I went to the trouble of finding it and getting it out myself and besides there was no guarantee that that one was going to work either. Turns out it didn't work. However, it was the motor part itself that didn't work—it seemed frozen—but the gear mechanism which the motor drives was fine and that was the part that actually went bad on mine. (More on the how and why of that below.)

The gear is in the round part at the top. The whole motor mounts upright on a bracket right behind the grill. There's a rod which slides through the center of the gear and clips on to the headlight covers at each end. So the motor turns the gear, which turns the rod, which moves the headlight covers down (open) and up (closed). Here's a picture with the gear cover off and the gear exposed...



Here it is with the gear actually out of the unit...



At first glance here the gear itself seems to be really two parts: the black part with the shaft that the rod slides through fits into the white toothed part...



The nuts you see inside are not original parts, of course, but were the eventual solution to my problem. Ignore'em for now...

This is where the actual problem was found. You may notice that the black part which fits into the white has a sort of "curved or rounded triangular" shape to it. The white part has a more obvious triangular shape to it too. Apparently there was originally a third part in between the two shown (in place of where the nuts are now), but due to age and weather (presumably extreme heat and cold) it had crumbled so that it just fell out as a pile of tiny broken pieces. (If you shook the gear before taking it apart it sounded like a tiny maraca.)

So as I said the motor I grabbed from the junkyard did not work, but the gear was intact. I didn't want to open up that gear and look inside for fear of damaging that mysterious inner part, so I just took the whole gear as a unit and placed it in my original motor, re-mounted it and it worked fine—for about a year. Then that gear went bad in exactly the same way. Apparently at a certain age that inner gear part is susceptible to decay and I imagine that once it starts crumbling it doesn't take long to disintegrate in there.

So back to square one this summer... I didn't want to mess around in a junkyard again since I couldn't be sure that any part I would grab would be any better than what I already had on hand or that it wouldn't soon go bad in the same way. So I had to figure if there was some way to fix the gear for myself. Without the mysterious disintegrated part in between the two halves of the gear, the white half just turned around the black half without actually turning the black half too (which thus would not turn the rod which lowers/raises the headlight covers). I have no idea why the two pieces weren't made to fit snugly together directly without the inner part, but I guess there must have been a reason.

I had to figure what I might be able to put inside to make the black half and the white half of the gear turn together so that the rod would also turn. My first thought was some kind of ballbearings, but I couldn't find any. Then I thought of nuts. I found some hexagonal nuts that were just the right size and used six of them (three pairs) strategically placed so that they just barely fit in the three main open spaces between the black and the white halves of the gear. (Refer back to the last picture above.) And I do mean just barely as it's a very snug fit to get the two halves back together with the nuts in place.

I re-mounted the motor unit with the rod through the gear and attached to the headlight covers, of course. Before re-connecting to the electrical system, I turned the knob on the bottom of the motor unit to make sure the headlight covers would be in the full upright (closed) position since the motor and covers should be in that position normally when the lights are off. I didn't want to make any mistake and have the motor and headlight covers out of sync so that I might try to open the covers when they were already open or close them when they were already closed. With the nuts inside making such a tight fit in the gear, if this happened I was afraid it might A) smash apart the two halves of the gear, B) damage the motor itself, or worst scenario of all C) do more significant damage to the headlight covers, the headlights themselves, and possibly even the body area around the headlights in general.

Amazingly enough, everything worked! Problem solved. It's been fine ever since. I just thought the solution was really neat in a Rube Goldberg kind of way and I'm sorta semi-proud of having come up with it. I wonder how much a Chrysler dealership or general auto mechanic would have charged for parts and labor...