1988/89 glass quad headlights: need adjustment procedure + stuck screws

[DennisT]

Need to clean, lube and generally recondition my wrecking yard '88/89 glass quad headlight brackets/assemblies. I'm trying to understand the half-dozen little gear-box looking mechanisms in this thing. I can see the from-the-front aim adjusting screws, but they seem stuck. I've lightly lubed them with plastic compatible lube, but they're still stuck. I really don't understand the right-angle, "gear boxes." A lot of mechanism/adjusters for only really needing up, down and sideways adjusting. And there are 2 pin-point torx screws for each lamp that appear to do just that. Why they run through those little boxes I cannot even imagine. Can anyone untangle me on this????? Is there a screw in this mess that locks the adjusting screw? I tried to find an owner's manual on line for these 2 years that would help, but none I can see. Thanks, Dennis

 

[Hipster]

Should have checked the adjusters before you left the yard. IMHO it's hard to get adjusters unstuck. Too much force and you inevitably break or strip the gears.

 

[DennisT]

Good point. I would have gotten them anyway, even stuck. They were cheap. I've found 3 thus far, so have a set-and-a-half. (One to ruin I suppose....) The screws accessed from the front, along side the glass lamps themselves, seem obviously to adjust. I just still don't understand the need for a little gearbox. And so many. And except for the threaded rods/adjusting screws, I'm not sure if much else is metal. Gearboxes seem plastic, so I guess internals are plastic too? It's just weird to my way of thinking. I wonder if anyone here has taken this stuff apart and recorded the process.
I'm in no hurry; winter project. So I'll continue to soak the parts a few drops at a time for a while. Much heat I think might be a bad idea.
Still hoping to learn more here.

 

[Hipster]

Good point. I would have gotten them anyway, even stuck. They were cheap. I've found 3 thus far, so have a set-and-a-half. (One to ruin I suppose....) The screws accessed from the front, along side the glass lamps themselves, seem obviously to adjust. I just still don't understand the need for a little gearbox. And so many. And except for the threaded rods/adjusting screws, I'm not sure if much else is metal. Gearboxes seem plastic, so I guess internals are plastic too? It's just weird to my way of thinking. I wonder if anyone here has taken this stuff apart and recorded the process.
I'm in no hurry; winter project. So I'll continue to soak the parts a few drops at a time for a while. Much heat I think might be a bad idea.
Still hoping to learn more here.

how about a pic of the lights?

 

[Donald Mitchell]

I just worked on some and only used a little oil on the threads and let it sit for a while. Later they worked good.

 

[someotherguy]

Back in the days before the composite lamp GMT400's pretty much everything was sealed beam; it was common to have seized adjusters when dealing with older vehicles. It was also common that we had to fight with them whether we wanted to or not, because TX state inspection used to require properly aimed headlights - the inspector actually used a dedicated tool that showed whether they were in proper adjustment or not.

So with that said, we were always failing inspection on our beat up old junk and having to hit the auto parts store to dig through the various adjuster kits hoping to find the right ones to replace the seized pieces. Oh and the screws holding the headlight bezels were almost always seized too, which is why I own a hand impact driver. (the spring-loaded kind that holds the screwdriver bits and you smack it with a hammer.)

Not sure what exact design the quad lamps use, haven't had to replace any.. but you may want to see what's available with some searching.

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Richard

 

[DennisT]

Hipster, here are photos. Top is spare unit. Early stages of clean up.

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[DennisT]

Someotherguy, that's a good story. I had no idea individual adjusters were available, of any kind. Don't see any that match yet, but now I have something to look for. Meanwhile, I'm going to cautiously soak the threads, etc., on mine and see what happens. They still seem over complicated to me.

 

[GoToGuy]

A company called Aveco, produced original and continues to produce alot of factory parts. ( it's amazing how many manufacturers use the same automotive hardware). The service manual has the headlight aiming procedures.

 

[DennisT]

Thanks. For a while I looked for a glove box Owner's Manual, thinking that might have headlight adjustment instructions. Probably a real, proper service manual, as you suggested, would cover it well. Since I'm adapting my 1996 to 1988/89 headlights only, I'm trying to avoid spending retirement money on a full manual for a truck I actually don't have. But I'll look on line again.