Headlight Alignment

[CELSI0R]

Hello,

I have been searching online recently for more details about the headlight alignment procedure, as I would like to check and re-align the headlights on my 1991 LS 400. However, I have been quite confused by the results and would like some more clarification about the process.

As described in the shop diagram image I attached, the A-bolt is for horizontal adjustment, and the B-bolt is for vertical adjustment. Do both of these bolts move the actual headlight lens or just the bulb inside? What I mean by this is, when you turn the A-bolt, can you see a visible change in the headlight moving left or right (with the lights off), and when you turn the B-bolt, can you see the headlight itself moving up or down?

Of course, I will be aligning the lights based off of where the beams are hitting a wall, opposite the front of the car, but I don't want to make the lenses look crooked as a result.

Also, when removing the rubber cover on the radiator support for the A-bolt, I'm assuming you can pull it from the top using your fingers(?).

Any clarification on this subject would be much appreciated. Thanks!

Note, the second picture of the actual headlight is from this thread.

[Spartan0536]

I adjusted my headlights like this and it worked as you described, it looks like it only moves the bulb inside.

To properly adjust my headlights I did the 5 - 15 adjust method...

Adjust your headlights to have a level beam pattern at 5 feet, then adjust again using a flat matte backdrop (black or white, some people say one is better than the other) you finalize your vertical pattern and horizontal pattern to angle the beam at the center of the car.

According to the NHTSA Halogen bulbs should cast light illumination on reflective signs out to 45 feet on low beam and cover a minimum of 90 degrees focus. With Halogen bulbs this means that bright light should be cast out to 15-20 feet, this will provide optimal illumination of the road and upcoming signs and potential hazards.

LED's are a bit different as their lumen output is 3x that of even performance Halogen bulbs, for them it's a 5-25-40 rule for adjustment

HID's are the brightest of the bunch, and generally are adjusted at 5-30-45.


Addendum:

The reason for the different distances especially when regarding the use of higher intensity lighting is that you do not want to blind other drivers, especially in oncoming traffic and maximize forward ground illumination where your eyes will focus on the road, this will not only make people hate you less but will enhance your chances of dodging potentially hazardous obstacles on the road at night.

@ 5 feet you make your more major adjustments in terms of vertical and horizontal

@ 15/25/30 feet you make more minute adjustments to ensure the beam pattern is centered and is level and is providing the correct amount of ground illumination and reflective sign illumination.

@40/45 (45 with Halogen on HIGH BEAM) feet you ensure that your lights are not blinding (exception for Halogen High Beam, will be separated). Finalize your beam pattern with very minute adjustments and give it a driving test starting out in your neighborhood then onto a highway.

*NOTE: For HALOGEN HIGH BEAM ONLY - When testing your high beams at 45 feet ensure that you have the correct side and height illumination and that reflective signs out to at least 100 feet away are being illuminated.

[CELSI0R]

Wow, thank you very much for all of the information, Spartan0536! I did not know those details about halogen bulb illumination. I'm sure this is going to help plenty of other owners with different setups, too.

I hope to get the chance to do the headlight alignment on my car soon..

[Spartan0536]

The only reason I know this is that my friend who is a cop was warning me about certain HID and LED upgrades that are either too dim or bright. He stated that the light from a bulb at minimum should reflect back at 45 feet and the sign should be visible, this is on low beam, and 100 feet on high beams to meet DOT and NHTSA specifications, otherwise expect a ticket for improper lighting equipment.

When it comes to HID's make sure they are angled DOWN more than up, their lumen output at low beam is 2.5x that of Halogens on high beams.

[Hadley Rood]

THIS MAKES SENSE TO ME.

 

HADLEY ROOD

 

 

 

 

[CELSI0R]

On 4/3/2017 at 5:47 PM, Spartan0536 said:

I adjusted my headlights like this and it worked as you described, it looks like it only moves the bulb inside.

To properly adjust my headlights I did the 5 - 15 adjust method...

Adjust your headlights to have a level beam pattern at 5 feet, then adjust again using a flat matte backdrop (black or white, some people say one is better than the other) you finalize your vertical pattern and horizontal pattern to angle the beam at the center of the car.

Hi again Spartan,

Just curious, did you have to turn the adjustment screw a lot to notice a difference in the horizontal beam aiming when you did your headlight alignment? I'm not sure if I'm seeing any difference in the headlight aiming, as I turn the screw clockwise or counterclockwise. Maybe it's already maxxed out in one direction and I can't move it anymore(?).

Also, did you notice if turning the adjustment screw clockwise moved the headlight left or right? This question is not as important as the previous one, but any help is appreciated!

[CELSI0R]

I went back to do the headlight alignment again. Here are some useful details for any UCF10/11 1990-1994 owners attempting this job:

To adjust the horizontal aiming of your headlight, remove the radiator core support hole plug, which will expose the A-bolt (see below diagram):


The hole plug in the radiator core support looks like this:


To remove this plug, simply slide your fingers under the outer edge, squeeze it slightly, and pull upward.

Once this is removed, you will see the horizontal adjustment screw (A-bolt) for your headlight:


Turning the A-bolt clockwise or counterclockwise will adjust the beam left or right.
[I did not notice a change in the beam pattern when I turned the A-bolt. If notice which way the light moves when the screw is turned clockwise, please reply to this post]

The B-bolt adjust the height of the headlight aiming. Turning the B-bolt clockwise will move the entire headlight and the beam upward, and turning the bolt counterclockwise will move the headlight down.

NOTE: It will take several turns in order to begin to notice a difference in beam pattern aiming and/or actual movement in the lens. If you don't see any changes after about 10 or more turns of your screwdriver, the adjustment gear might be stuck or broken. You can keep trying to turn it, to see if it changes. Do not rush the process, or you may strip the gears. You may hear some slight rubbing when rotating the B-bolt.