Headlight Puzzle

Pilotdave

Pilotdave

Well-known member
I have run into a puzzle with the headlights in one of our A's.

I'm using the new Bratton's reflectors and 50/32 bulbs. The reflectors are installed with the "Top" marking at the top. The slot in the reflector "tube" thus determines the orientation of the bulb socket.

Using a welding mask and with the light switch in the high beam position, I can see that the lower filaments of the bulbs are on; in the low beam position the upper filaments are on. The upper filaments are slightly offset from the center line of the bulbs.

Sounds good so far, right? Here comes the puzzle. I have been following the focusing process outlined on Marco Tahtaras's website.

With the lenses removed, I can track a 12" disc of light on the wall, about 5.5 feet in front of the headlight. I have performed the following several times, again using a welding mask to observe which filament is on: When I switch from high beam (lower filament) to low beam (upper filament), the light disc moves UP slightly - not DOWN as I expected it would. Is this normal behavior?

Thanks!
Dave
 
Sounds to me like the filament is not in the correct place. It should be right at the focal pont of the reflector. If it is in front, the beam will go one way when you dip, if it is the other way, it will go in the opposite direction.
 
Older reflectors are wont to have the bulb socket ferrule "turn" - thus losing the orientation between the rim and the bulb ferrule/bulb.

New reflectors seemingly have solved this issue (along with proper parabolic curvature) but yours might be a quality issue.

As originally designed EVERYTHING goes together in the proper - and only - orientation. And one gets the "lower filament high beam" "upper filament low beam" in their proper spots.

Vince Falter (my go-to guy on technical details) addresses issues with the reflectors. See http://www.fordgarage.com/pages/Aheadlampreflectors.htm

He notes

The optical performance of the reflector cannot be optimized with the wrong parabolic shape or dimensions, nor with the use of higher powered halogen bulbs. It will just result in low performance high glare headlamps. They may be bright with high power bulbs, but they cannot focus and put the light to the lens in the proper direction. The result is just light scatter and glare.
The bulb socket is adjustable fore-aft in the reflector via the screw on the back of the headlamp housing. This allows the bulb filament to be properly placed at the correct focal point of the reflector for optimum lighting performance.
Click to expand...
I'm guessing, getting the proper forward-back location of the bulb will probably resolve the "reverse" bulb imprint. May not be possible with the brighter bulb.

Joe K
 
Remove the reflectors and measure from the throat of the sleeve to the rim. There should be about 1/8" difference. The shorter measurement goes to the TOP. Possible they were marked wrong. Two-bulb reflectors are easier; the park bulb goes above the main bulb.

Hm-m - if they were assembled upside-down, the slot in the sleeve would be on the wrong side - swap wires or send them back.
 
Thanks, everyone, for all your replies/suggestions. I believe that we're on the same page as to how the headlight is supposed to be assembled! I will double-check the sleeve-to-rim measurements to make sure that the reflectors are correctly labeled. I'm also going to repeat the "which filament is lit" test to verify that what I've described is the case.

One question based on Badpuppy's reply: standing in front of the car and facing the reflector, should the slot in the sleeve be on the driver's or passenger's side? Mine are on the driver's side.

Thanks, all.
Dave
 
I have measured the reflectors as suggested. There's about 1/16" difference with the shorter measurement on the top side, suggesting that these Bratton reflectors are as advertised.

I also repeated the filament test. Turns out that one headlight was wired backwards - correcting that resulted in the light disc on that light moving down when changing from the high to low beam setting. The universe is back on its proper axis!

I appreciate all the input and help on the above and turn to a couple of fine-tuning adjustments that may be associated with manufacture of the headlight buckets and bezels.

First, the lenses are not quite properly oriented in that the horizontal flutes are not parallel to the ground. This is linked to the location of the metal tab in the bottom of the lens bezel - it seems to be slightly off its proper location - that locks into the notch in the lens. The bezel itself is oriented by the mechanism that locks the bezel to the headlight bucket. It appears that the solution is to remove some or all of the tab so that the lens can be rotated so that the flutes are parallel to the ground. Or is there another solution?

Second, the "top" spot on the reflector is not quite at the 12 o'clock position. This in turn causes the socket to rotate a few degrees so that its notch will fit into the slot in the reflector sleeve. Which causes the two filaments to not be parallel to the ground. This is being caused by the location of the two "bumps" (3 and 9 o'clock) in the headlight bucket that are supposed to mesh with the two notches in the edge of the reflector; the two bumps appear to be off the 3-9 o'clock positioning by a few degrees. Is there a way to adjust this?

I'd like to fix these as I suspect that either or both contribute to not getting the maximum performance from the headlights. Thank you for any ideas to address them!
Dave
 
Pilotdave said:
One question based on Badpuppy's reply: standing in front of the car and facing the reflector, should the slot in the sleeve be on the driver's or passenger's side? Mine are on the driver's side.

Thanks, all.
Dave
Click to expand...

Slot is on vehicle left (driver's side in civilized countries :D).

The tilt you describe is odd. Both headlights? Check the mounting bar and hardware before chopping up the bucket plate.
 
Last edited:
Thanks, Badpuppy and Kurt. My slots are where they belong and my bulbs are recent repros.

I'm happy to report that the problem is fixed. This morning I realized that the issues I described in #9 could be cause by the entire headlight bucket (both of them as it turned out) being tilted off a vertical plumb line. The center of the U-shaped clip on the bottom of the bucket needs to be directly under the center of the words stamped on the top of the bucket for the bulb filaments and the lens flutes to be properly positioned. So....I went looking for something that could cause this to not be the case and realized that there's some "give" in the bucket bolt/headlight bar connection. (Thanks, Marco, for your PM confirming this.) Loosened the buckets and straightened them - corrected both the bulb alignment problem and the lens fluting issue. Nothing wrong with the bar or the buckets or the bezels or the bulbs.......just a simple alignment problem. Moral of this story might well be "check the simple stuff first"!

Thank you to everyone who thought about/replied on this thread. It's really helpful to have people who can confirm/correct/query and prod!

Dave
 
You must log in or register to reply here.
Back
Top