And today, I finally fixed it.
I’m talking of course, about my headlight shaking. The drivers side headlight has wobbled when going over minor bumps ever since I bought the car, and for a good year I assumed it was an electrical fault causing the light to flicker. Then I installed new coilovers, and noticed that when I set stiffness to max, the headlight was shaking like crazy on even the most casual, laid back drives... Hmm.
In addition, the old, stock headlights were absolute garbage, so I figured I’d buy new, fancy LED enclosures to hopefully kill two birds with one stone. Well... The lighting upgrade was incredible, but the shakyness remained. That and a few tests while stationary, meant it was a mechanical and not electrical issue. It was time to solve this problem.
Step One - Remove outer casing
Pinpointing the problem would be a lot easier if I could see the inner workings of the headlight housing. That meant getting all of the covers out of the way! First, headlights go up. Also hood. Second, remove the headlight shroud, a black plastic cover that goes around the headlight and under the body-color headlight cover, designed to keep the elements out. Four screws and some careful jiggling and it’s free. That reveals the four bolts holding the headlight cover in place. They have indentations for a Philips head screwdriver (I mean, a JIS screwdriver) but they strip out instantly so I wouldn’t recommend that method. Once the headlight cover is off, press the pop-up button to lower the lights, drop the hood and consider for a second how the NA Miata would look if it had no pop-ups and the hood was instead a perfect rectangle.
Step Two - Tighten all bolts on the headlight housing hinge
The headlight housing had a lot of slack, easily half an inch of play when in the “up” position. There should be absolutely zero. Therefore my first thought was that something must be loose. Seems logical right? Anyways, the headlight housing connects to the frame at two points—basically a hinge on either side—and a motorized arm pushes/pulls the housing around that hinge to determine whether the housing is in the “up” or “down” position. I tightened the two bolts, one of which you can see I’m the image above.
That did absolutely nothing... So I tried tightening the bolts holding the mechanical arm in place on both the headlight housing side, and the headlight motor side. Again, still wobbly. There were no other bolts I could tighten, so I was beginning to think the frame that the headlight housing was hinged to might just be damaged. This car did have a front-end collision in its past after all.
Step Three - ask yourself what you’re missing. Look closer.
Not ready to throw in the towel, I stepped back and tried to think about this in a different way. The whole reason I was here was because my lights were shaking terribly while driving, which was bad for visibility and looked like something you’d see on a beat-to-shit Chrysler with one hubcap, which is not something I want my poor Miata to be compared to. It was fairly easy to see that a loose driver’s side headlight enclosure was the cause of the problem, but I was at a loss as to how I could get rid of the slack.
Until I noticed a tiny rubber bumpstop underneath the headlight housing. I did some forum sleuthing and found out that there was a bumpstop to keep movement out of the headlight assembly in the down position, and another bumpstop with the same job for the up position. The down position bumpstop which I found, worked perfectly. The up position bumpstop obviously did not. I also didn’t SEE that bumpstop, because I’d been working with the headlights in the “up” position which completely blocked view of the up position bumpstop. Being the genius that I am, I dropped the headlights with the flick of a switch and found what I was looking for. In the center of the image below you can see a very old, rock hard bumpstop. I these bumpstop are adjustable. Loosen the nut on the bottom of the headlight housing, and you can twist the bumpstop to raise it up a few millimeters. My nut was stripped, because of course it was. So instead of raising the bumpstop... I “lowered” the surface that the bumpstop was supposed to make contact with. The long out-of-focus metal extension below accepts the rubber stopper, becoming a point of contact between the headlight housing and frame, eliminating movement. I duct taped some leftover flooring underlay to the bottom and raised the headlights. Success! No more wobble!
Ended up spending two hours on what I seems like an incredibly simple fix I’m retrospect, but that’s how it works I guess. Took the opportunity to also properly align my headlight covers in relation to the hood and bumper, which was another minor irritation about the car. All in all I’m super excited to drive without flickering headlights, and equally excited to have started and finished a project on my own without breaking something haha
This was also the first time using the new socket set. Having a set with everything I’d need, all organized in front of me is a game changer. My only complaint so far with the Williams set is pretty minor. The ratcheting mechanism is super quiet, and I miss the loud clicky sound I’m used to with various Craftsman socket wrenchs. Like I said, minor!
Last but not least, shout out to the dude on this forum for writing up such a wonderful reply. Look at all the info this post. The detail. The explanation. The explanation behind the explanation. It’s beautiful