Awesome thank you!! I couldn't even find that info in the service manual! Honestly the lmc with glass is nice. I hate composite I was just hoping for a decent output with these little lights. It's a shame glass is a thing of the past. If I can get them adjusted lower I'll get some pics of the beam pattern and cutoff line just to give an idea how they compare.
'88/89 Glass Quads' Achilles Heel- The Adjusters!
- Thread starter DennisT
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Yeah I'm honestly surprised the aftermarket is so lacking for them with how common they were in different applications. Yeah I hope I can get mine working. If not I'll swap to the single sealed beam setup with the work truck grill I have on the bench. Those were used in everything and super simple
DennisT
I'm Awesome
I would be really curious just how many rigs had these little lamps. Moreover, what bucket assemblies held them? !! Because, another poster mentioned having, "scored," high quality lamps from a GM, "Vandura," in a wrecking yard. (It had aftermarket, good glass replacements like we appreciate) Well, I came across one of those Vanduras a few weeks ago in a local wrecking yard. Yup. Same little glass sealed beams. Factory sealed beams, which, we know, were mostly worthless. I pulled the lamp surround and removed the sealed beams. Behind, I discovered the mounting was totally different from our trucks. So NOTHING on that Vandura was of any use to me, (or any of us). Therefore, of all the vehicles with little headlights, there are likely very few with interchangeable adjusters. Those Pontiacs? All this making used parts sourcing even worse for us.
And you're right, the W/T, entry level single 5x7 headlight front ends are the best option if one likes the look. I have that on my '90 3500 Telco utility truck. They just look bland to me, although some guys dress them up pretty nice. Daniel Sterns Lighting has the killer setup for the W/T headlights.....just expensive...... But worth it. I have that setup in my '99 Cherokee-same headlight size.
And you're right, the W/T, entry level single 5x7 headlight front ends are the best option if one likes the look. I have that on my '90 3500 Telco utility truck. They just look bland to me, although some guys dress them up pretty nice. Daniel Sterns Lighting has the killer setup for the W/T headlights.....just expensive...... But worth it. I have that setup in my '99 Cherokee-same headlight size.
GoreMaker
Newbie
Bringing this back from the dead with some answers. Today I planned to do the quad sealed beam swap on my 1999 Suburban, but of course all the adjusters on the used units I got were seized up. Came upon this thread, and didn't really find any answers. Also couldn't find new units anywhere online. And I sure af wasn't gonna spend $300 x2 on complete new units just for a bunch of adjusters. So I took the plunge and opened one up to figure out what the deal is. I used a Dremel to cut around the outside of the cylindrical housing for the driven screw (the one that hooks into the headlight bucket) and popped it open. Here's a breakdown of how it works inside:
Very first thing is a brass washer:
Under the washer is a brass gear:
The brass gear is driven by another one that's attached to the top screw, the one we turn to do the adjusting. Removing the driven brass gear shows a plastic (nylon) threaded sleeve:
And that's the cause of ALL the problems. That threaded sleeve is seized onto the driven screw. There's zero lubrication from the factory. Before I opened up the housing, I had tried penetrating fluid to see if that could loosen things up, but that was before I realized I was dealing with nylon threads. Penetrating fluid makes things worse because it causes the nylon sleeve to swell and grab the screw even tighter. This sleeve grabs a LOT of thread, so it creates a death grip on the screw:
Once I realized what the problem is, the solution was simple. I grabbed the driven screw by its head in my vice:
Then I used a heat gun to warm up the plastic sleeve, while trying to twist it with pliers. There's very convenient flat spots on the shaft of the sleeve, so there's no risk of damaging the gear interface:
And sure enough, after a couple minutes, the sleeve freed up and I was able to twist it all the way off. I cleaned off the threads on the driven screw using a metal wire brush on a drill. All the corrosion I found on the threads was from brass shavings. So the brass gears create shavings as the adjusters are turned, those shavings end up on the threads of the driven screw, and they find their way between the metal threads and the nylon sleeve, which causes everything to seize up.
I sprayed the driven screw down with PTFE lube. This is a dry lube with a solvent that evaporates quickly, so it doesn't swell up the nylon. WD40 sells it in a spray can that's very convenient. I also sprayed some PTFE lube inside the nylon sleeve. Then I reassembled everything. I put the cap back on the cylinder housing and glued it into place using Gorilla gel super glue around the outside edge. It all turned super smoothly with zero binding.
Now that I understood what the problem was, I used a different tactic for the next adjuster. I put it in the vice holding the driven screw head again, then I used a soldering iron to apply heat to the tip of the driven screw:
With a T15 Torx screwdriver, I gently twisted the adjuster back and forth while heating the driven screw. After a couple minutes, the sleeve inside freed up. I continued to apply heat while working the driven screw out of the housing until it was relatively easy to turn, then I removed the soldering iron and finished removing the screw so the nylon sleeve could cool and form itself properly to the threads. Once the screw was out, I cleaned it up with my wire brush again, sprayed PTFE lube all over it and inside the adjuster, and put the screw back in. This should give an idea of how successful I was:
So there we go, a solution to seized adjusters on quad sealed headlights. And anyone can do it with a simple soldering iron and some PTFE lube. no need to open up the adjusters at all.
Very first thing is a brass washer:
You must be registered for see images attach
Under the washer is a brass gear:
You must be registered for see images attach
The brass gear is driven by another one that's attached to the top screw, the one we turn to do the adjusting. Removing the driven brass gear shows a plastic (nylon) threaded sleeve:
You must be registered for see images attach
And that's the cause of ALL the problems. That threaded sleeve is seized onto the driven screw. There's zero lubrication from the factory. Before I opened up the housing, I had tried penetrating fluid to see if that could loosen things up, but that was before I realized I was dealing with nylon threads. Penetrating fluid makes things worse because it causes the nylon sleeve to swell and grab the screw even tighter. This sleeve grabs a LOT of thread, so it creates a death grip on the screw:
You must be registered for see images attach
Once I realized what the problem is, the solution was simple. I grabbed the driven screw by its head in my vice:
You must be registered for see images attach
Then I used a heat gun to warm up the plastic sleeve, while trying to twist it with pliers. There's very convenient flat spots on the shaft of the sleeve, so there's no risk of damaging the gear interface:
You must be registered for see images attach
And sure enough, after a couple minutes, the sleeve freed up and I was able to twist it all the way off. I cleaned off the threads on the driven screw using a metal wire brush on a drill. All the corrosion I found on the threads was from brass shavings. So the brass gears create shavings as the adjusters are turned, those shavings end up on the threads of the driven screw, and they find their way between the metal threads and the nylon sleeve, which causes everything to seize up.
You must be registered for see images attach
I sprayed the driven screw down with PTFE lube. This is a dry lube with a solvent that evaporates quickly, so it doesn't swell up the nylon. WD40 sells it in a spray can that's very convenient. I also sprayed some PTFE lube inside the nylon sleeve. Then I reassembled everything. I put the cap back on the cylinder housing and glued it into place using Gorilla gel super glue around the outside edge. It all turned super smoothly with zero binding.
Now that I understood what the problem was, I used a different tactic for the next adjuster. I put it in the vice holding the driven screw head again, then I used a soldering iron to apply heat to the tip of the driven screw:
You must be registered for see images attach
With a T15 Torx screwdriver, I gently twisted the adjuster back and forth while heating the driven screw. After a couple minutes, the sleeve inside freed up. I continued to apply heat while working the driven screw out of the housing until it was relatively easy to turn, then I removed the soldering iron and finished removing the screw so the nylon sleeve could cool and form itself properly to the threads. Once the screw was out, I cleaned it up with my wire brush again, sprayed PTFE lube all over it and inside the adjuster, and put the screw back in. This should give an idea of how successful I was:
You must be registered for see images attach
So there we go, a solution to seized adjusters on quad sealed headlights. And anyone can do it with a simple soldering iron and some PTFE lube. no need to open up the adjusters at all.
someotherguy
Truly Awesome
DennisT
I'm Awesome
Amazing!!!! Thank you so much for updating my original post on this problem. I would have saved many hours had I known this back then. I am certainly saving all this for future reference!
Dennis
Dennis
GoreMaker
Newbie
It took me about an hour to get all 8 adjusters spinning freely again. I'm very happy with the result, the headlights adjust extremely well now
A big high five to you mate, that thread would of taken a lot of time to correlate and post. For those of us that have difficulty learning from text that thread made all of the difference. This is the sort of effort that makes this forum so good. Thank you.
someotherguy
Truly Awesome
I'm digging the info on PTFE lube being the product to use and hearing that penetrating oil swells the nylon. Wouldn't have guessed there was nylon in there but then again, plastics of one kind of another have been used in headlight adjusters (usually the exposed type) for decades.
At this point anybody trying to maintain these up to 35 year old trucks should have developed soldering skills and have basic soldering equipment around the garage already, IMO. The cost of even a cheap but usable soldering iron pays for itself almost right away with 1 wiper motor fix.
Richard
Similar threads
Members online
- 99xcss4
- SAATR
- Greatphilip
- Road Trip
- burban454
- JS45
- 618 Syndicate
- Mg guy
- L31MaxExpress
- solaralexx
- Aqua-pig
- Alteca
- VictoryRed
- smdk2500
- bowtie454
- movietvet
- Odeezy
- EastAZfab
- Z71Hobbs
- Wildcat465
- Komet
- 96stepsideobs
- TX97z71
- JPVortex
- Drunkcanuk
- jays96
- scott2093
- GrimsterGMC
- nicksuspect
- hunterjdenny
- Laredo
- SNCTMPL
- PlayingWithTBI
- Tombbo
- HotWheelsBurban
- Thatrebelboy48
- name
- OldschoolPT
- Carlaisle
- Rob93z71
- Thatlowchevy
- screetsweepr
- Arthurius
- 0xDEADBEEF
- Caman96
- nickc2500
- Orpedcrow
- dakaduh
- toolmantim277
- Jlojub