Cab Light Mount Questions

A couple of basic questions about adding cab lights - devil's in the details as they say.

Got these mounts:

One on the left is a GM original. One on the right (hardware store) is the same thread and size (trunk is a tad thicker) - but rubber instead. I like the rubber one but it would require a larger hole to be drilled. How does the stock metal GM one mount? (not 100% sure how the rubber one installs either). Does it expand like a rivet? Looks similar to those anchors they use for the door mirrors. I could dab it with panel adhesive if need be. Dunno.

Nuther question: what size /color bulbs do you guys use? Going LED of course - the 168 is slightly brighter than a 194. Also need to find a GOOD LED bulb - most everything is chicom - just need to find a better brand.

I mocked one up and was kind of meh on the output of the clear bulb with amber lense. No idea what an amber bulb would be like.

Just thinking out loud before holes get drilled.....

THX

The factory lights are screwed into nuts that are welded into the sheet metal. The bulb socket is held by the lens gasket.

When I retrofitted them to the Suburban I used Nutserts. They're machine screws, not sheet metal screws.

Blue Ox said:

The factory lights are screwed into nuts that are welded into the sheet metal. The bulb socket is held by the lens gasket.

When I retrofitted them to the Suburban I used Nutserts. They're machine screws, not sheet metal screws.

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I wonder if nutserts could be used for the door mirrors also? I realize I digress but that will be a future issue. This truck is like death by a thousand cuts to me. lol

Doppleganger said:

I wonder if nutserts could be used for the door mirrors also? I realize I digress but that will be a future issue. This truck is like death by a thousand cuts to me. lol

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Yes, low mount mirrors also have an internal reinforcement.

Doppleganger said:

I wonder if nutserts could be used for the door mirrors also? I realize I digress but that will be a future issue. This truck is like death by a thousand cuts to me. lol

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fast 99 said:

Yes, low mount mirrors also have an internal reinforcement.

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Just from cr@ppy memory I think the mirror screwed into plastic inserts, but you'll definitely need that internal brace.

I think these anchors need drilled out? The bottom one IIRC is the one with the steel brace. Seems this has been covered but I dont remember where.

That original GM piece looks to just be a nutsert. It's been many years since I had the cab lights off of my '79, but I don't remember it having the special stamped roof skin with nuts pressed and welded to the skin for the lights, like on the later models. If I pulled a lense off to refresh my memory, I'll bet I find nutserts.

bucket said:

That original GM piece looks to just be a nutsert. It's been many years since I had the cab lights off of my '79, but I don't remember it having the special stamped roof skin with nuts pressed and welded to the skin for the lights, like on the later models. If I pulled a lense off to refresh my memory, I'll bet I find nutserts.

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I found them called 'well nuts' and they apparently bulge when you thread a screw into them....like the cheesy wall anchors in drywall. Will probably use those since thats what comes with the GM kits.

Now to find whatever that door mirror uses.

Doppleganger said:

I found them called 'well nuts' and they apparently bulge when you thread a screw into them....like the cheesy wall anchors in drywall. Will probably use those since thats what comes with the GM kits.

Now to find whatever that door mirror uses.

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Yeah, well nuts is another name. They take more force than that to install though. They install like a big rivet. The use of a rivnut install tool is by far the best way to install them, but you can do the same thing (carefully) with a long bolt and a stack of washers. There are several types of install tools, some cheap and some that are more expensive.

If just using a bolt and washers, I'd recommend against the GM ones. I'd get some commonly available rivnuts that have a serrated shell, to prevent them from spinning during the install.

I splurged and bought a nutsert kit. Has the tool, various aluminum and steel nutserts. I put that S**T on everything! Best thing I ever bought. Except for maybe the weather pack connector kit.

bucket said:

That original GM piece looks to just be a nutsert. It's been many years since I had the cab lights off of my '79, but I don't remember it having the special stamped roof skin with nuts pressed and welded to the skin for the lights, like on the later models. If I pulled a lense off to refresh my memory, I'll bet I find nutserts.

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My cab definitely has factory clearance lights and there is a D shaped depression stamped into the sheet metal with a square nut welded or brazed into it. Not saying they're all like that, but mine is not a Rivnut or Nutsert, it's part of the roof. There may have been a change made in the '81 refresh, so your '79's configuration may be an earlier version.

Blue Ox said:

My cab definitely has factory clearance lights and there is a D shaped depression stamped into the sheet metal with a square nut welded or brazed into it. Not saying they're all like that, but mine is not a Rivnut or Nutsert, it's part of the roof. There may have been a change made in the '81 refresh, so your '79's configuration may be an earlier version.

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Yeah, that's what I was trying to get at, that there was a design change at some point and the earlier trucks didn't get a dedicated roof stamping for the cab lights.

For the trucks anyway. Does anyone know if the Suburbans wound up with a dedicated roof stamping as well? So few of them (comparatively) were ordered with cab lights, that would be an expensive manufacturing change, I'm guessing. Large roof and low production.

I never removed the lights from my '90 Burb to know what was under them. They were indeed factory installed though.

SquareRoot said:

I splurged and bought a nutsert kit. Has the tool, various aluminum and steel nutserts. I put that S**T on everything! Best thing I ever bought. Except for maybe the weather pack connector kit.

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Which one did you get and how does it differ from a pop riveter?

You’re overthinking it….get some riv nuts, nut serts, blind nuts, whatever and pop them in. It’s holding a teeny tiny light with 3 screws. It will hold longer than you’ll be driving the truck.

@Doppleganger
It has different size "rods" depending on the size of nutsert you're using