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

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Frank Enstein

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The adjuster screws on the headlamp buckets aren't supposed to turn. They fit into a squared-off U shaped groove.
Be nice to them or they will tear out of the bucket.

Three of them broke on me when I did the quad light conversion in Frank so they are soldered to the light buckets.

Remove the springs from the buckets so you can remove it. This makes it easy to get the buckets out.
DON'T mix up the buckets or the lamp retaining bezel.

Now you can hold the screw that gets slotted into the bucket with some pliers to hold it while you gently work the other screws loose.

Be gentle and perseverant and they will come loose. I like the Tri-Flow lubricants.
I also like to lube the pads that touch the buckets with some silicone/Teflon based grease. You'll thank me if you do that.

Sylvania has some upgrade 4701 Hi and 4703 Low headlamps that are pretty good.

Clean and paint the buckets nice, reassemble, and start the aiming process.
 

AuroraGirl

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Dont use wd40 on plastic bits for the lube part, be like frank and PTFE/silicone after you get it moving.

Also, I have a 1990 olds 88 with OE glass headlamps and its going to be parted so I dont need anything on it.
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I also dont expect it to, but I have a 80 cutlass with probably something close but probbaly no dice kinda thing. I just mention so if you find out they cross I can check
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I also have a 79 with what looks like the larger single kind size?
 

Hipster

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Dont use wd40 on plastic bits for the lube part, be like frank and PTFE/silicone after you get it moving.

Also, I have a 1990 olds 88 with OE glass headlamps and its going to be parted so I dont need anything on it.
You must be registered for see images attach

I also dont expect it to, but I have a 80 cutlass with probably something close but probbaly no dice kinda thing. I just mention so if you find out they cross I can check
You must be registered for see images attach
You must be registered for see images attach

I also have a 79 with what looks like the larger single kind size?
Wd is fine on plastics. Used car detailers will spray down an entire engine compartment with wd to make the hoses , engine covers and door gaskets, exterior trim, other rubber bits look new. It's been done for decades without an issue. There are several ptfe/silicone free rubber lubricants available for bodyshop use.

It doesn't stay wet forever, Isn't goo so cleans up nice, and you don't end up tracking it all over the paint work but has a lot of uses such as window rubbers so the windows slide nice etc.
Kent and Sprayaway both make drylube aerosols for rubber and plastics that go on wet and dry up and would be good in this situation after they are freed up.

Bar soap worked in will also keep them unstuck.
 
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AuroraGirl

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Wd is fine on plastics. Used car detailers will spray down an entire engine compartment with wd to make the hoses , engine covers and door gaskets, exterior trim, other rubber bits look new. It's been done for decades without an issue. There are several ptfe/silicone free rubber lubricants available for bodyshop use.

It doesn't stay wet forever, Isn't goo so cleans up nice, and you don't end up tracking it all over the paint work but has a lot of uses such as window rubbers so the windows slide nice etc.
Kent and Sprayaway both make drylube aerosols for rubber and plastics that go on wet and dry up and would be good in this situation after they are freed up.

Bar soap will also lubricate threads.
oh god... Im just imagining now that horrific idea of WD40 on eeverything. I dont want petroleum based stuff
Used car dealer does not inspire any hope LOL
It does help you are removing it right away of course but id rather stick to using it for what its meant to and It does it OK but not like the best but its versatile yes. I use seafoam deep creep with good luck for cleaning/cutting crud away. also oils guns nice
 

Hipster

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oh god... Im just imagining now that horrific idea of WD40 on eeverything. I dont want petroleum based stuff
Used car dealer does not inspire any hope LOL
It does help you are removing it right away of course but id rather stick to using it for what its meant to and It does it OK but not like the best but its versatile yes. I use seafoam deep creep with good luck for cleaning/cutting crud away. also oils guns nice
LOL. I've never worked for a used car dealer, but I've done it myself. Actually makes things look really good.....for about a week until it dries up.. Main point being it's not going to mess with plastic. I prefer the drylube product's I mentioned for situations like we're discussing here. Lubricant's that lay wet tend to accumulate grit.
 

Hipster

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and if they're not available new.......

Richard
I think they were either serviced as a headlight bucket or complete assembly. I've done collision work on tons of them years ago and remember pulling complete assemblies with the bulbs and all out of GM boxes, bolt'em in , aim with a shadowbox set-up, and away they went.

In factory parts manuals it's not all that uncommon to find a parts number assigned to a part that was never serviced individually.
 

DennisT

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FrankE: thank you. I was initially really confused as I wondered if these lights were designed to be adjustable from front and/or top. Now, I believe they are only intended to be adjusted from the top, which probably only requires the truck's hood to be opened. I had noticed the squared bucket notches retaining the screw heads and was puzzled because that would be hard to turn unless some engineer intended it to be, "click stops," which didn't fully make sense either. You cleared all that up. Your other tips were really good too.
AuroraGirl, thank you for the tentative offer from your other cars. I have no way to know if anything from them crosses or not. I'm guessing not, unless the adjusters alone might be the same. ???
Hipster: more good tips. Oh...., and I'll bet your right: during the brief two years these quads were offered, entire units were probably swapped out in commercial shops. What I'm trying to do would have been awfully labor intensive even back then.
 

TechNova

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TechNova, I think you've wrapped it up. Aveco that SomeOtherGuy mentioned, I checked. Nothing like I have, but it opened up a new world of parts I knew nothing of. Worth it just to look. So what I've chosen to play with for headlights is part of a 2 year run that was never backed up well with repair parts. I often pick the real headaches to work with. Ha. The one-and-a-half sets of light brackets I found so far are the only ones I've seen around here. This won't be done until Spring, so I'll likely find 2 or 3 more for back up by then.
Even thought I buy alot from Auveco they a terrible website. Henry's Automotive has a good catalog they will send you
 

1989GMCSIERRA

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The 4 torx at each corner simply hold the trim ring that holds the actual headlight glass housing. Nothing to adjust.
your headlight adjustment is made on the two metal tabs at 9:00 and 12:00 that are the headlight bucket. The 12:00 aims up and down and 9:00 left to right.
the headlight connector is available online. I would go buy a plug connector and make a harness if yiure adapting to a different year than the 88/89 models. I think by 1990 they went to a one piece flush headlight with a different connector style

i would soak the heck out of them. Once you got them loose I would remove everything and wire brush all screws. Sandblast the rust treat the metal and then sand primer and paint. Reinstall everything. Lots of work judtvto get quad headlights but as a owner if a quad headlight truck I get the reason. It’s distinctive
 
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DennisT

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Thanks, 1989GMCSIERRA: This is turning into a lot of work, but, like you, I rather like the distinctive look as well. I'm in this far, so will keep going. It's the adjusters that are the big headache for me now. So much so, that rather than dragging this thread out to infinity, which has addressed many different aspects of these headlights, I' going to post a new thread on just the adjusters.
 
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