I have my headlight assemblies pulled apart for a rebuild. Also replacing the adjuster screws. Does anyone have a procedure to perform an alignment without one of those fancy alignment tools? I prefer todo all I can myself rather than have a garage do it. Hoping that someone on the forum has a 'Do-It-Yourself' procedure.

 

It's quite easy to make an aiming grid on your garage door or some other surface providing you have a level area to do it. The procedure is in the GM service manual. If you don't have the manual, post again and I'll be happy to type it up.

 

My 1978 service manual has a few words on the adjustment screws but no mention of the grid/specs...etc. If your manual has that I would really appreciate it if you could scan/email it or type out what you can. Thanks BigFish.

 

i also could use that info,for mine need adjusting also

 

Okay guys, I'll try to describe this but pictures might be easier.

1. Place vehicle on level floor with headlamps 25 feet from screen or light colored wall. Fuel tank should be half full and no passengers in the car. Clean the headlights and check for proper tire inflation. Make sure the car is square to the screen. If you are in doubt use the "3,4,5" method to extend a chalk line to square up the car.

2. Grid construction: I used black duct tape on my garage door, peeled it off the roll in 1/4" strips. I would suggest drawing this on a piece of paper as you go along through these instructions.

Make a horizontal line the same height from the ground as the center of the headlights. Make the line long enough to be slightly wider then the car. We will call this line #2.

Make a vertical line to represent the exact center of the car, extend the tape just a couple inches above and below line 2. We will call this line #4. (this is just a measuring point, not used for aiming)

Make 2 vertical lines same as line 4, but centered on each OUTER headlight. Extend these lines a foot or so above and below line 2. Measure from the center of the hood to center of the light to get this dimension. We will call the left line #3, and the right line #5.

3. With only low beams on, adjust the aiming screws to place the high intensity zone of the headlight beam just touching the bottom of line 2 and just touching the right sides of lines 3 and 5.

4. Cover the low beams and activate the high beams. Adjust the high intensity zone of the headlight beam to center of the intersection of line 2 and lines 3 and 5. In other words, the brightest part of the beam should aim directly at the cross made on the grid on both sides.

The headlight aiming procedure should be done only after the headlight housings are aligned. I'm afraid you will need pictures for that part for sure. Good luck, I hope this helped. I am very satisfied with the performance of my headlights after following this procedure.

 

Wow, that's great information. I usually get them close then road test and adjust. It'll be nice to start out with them correct.
BTW, what happened to line #1? Joe

 

Joe, I took those line designations right from the book. Line 1 actually represents the obround shaped light pattern from the headlight beams. Of course the real reason I didn't include a line 1 is because I wanted to baffle and confuse everyone

Hopefully everyone knows what I meant by the "3,4,5" method to square up the car to the screen. I would actually use a 6 foot, 8 foot, and 10 foot layout on something like this.

 

Thank You Big Fish!!! This is exactly what I was hoping would exist! I did find the housing adjustment procedure in my manaual, but not the headlight portion. Was it in another section of the manual? Perhaps the 1978 version does not have this at all.