What did you do to your NNBS GMT900 Tahoe/Yukon Today?

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the_tool_man

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If you mean the flip-top caps that the bolt goes through the bottom half then the cap snaps over it, I decided against this style because I'd expect the plastic to warp, shrink, dry rot, etc. in the sunlight and heat and, eventually, the caps wouldn't stay snapped closed.

If you were talking about the caps that are basically a disc with a hex-shaped recess to fit over the bolt head, that would work as well but would need to be adhered somehow. They would also sit much higher off the roof than caps snapped into set screws that were flush with the roof line. Thread sealer, such as what is used on bolts that protrude into water jackets in engine blocks should be plenty sufficient as it is (obviously) heat- and water resistant. The flat caps I'd snap over the set screws would have a layer of adhesive sealant (windshield adhesive, etc.) applied to the underside to secure them as well as seal them from the outside. Windshield adhesive is designed to adhere and seal and not weather, so it's ideal. When I press the cap onto the set screw, the adhesive will squish out around the edges. I'd just wipe off the escess while it's still wet. The threaded insert will be completely encapsulated by plastic that's covered by body paint and UV-reflective clear coat as well as adhesive sealant designed for such a purpose. The flat caps would be maybe 2mm high rather than the hex bolt caps which would stand off the body the thickness of the bolt head plus the thickness of the plastic itself. The lower profile would be much cleaner.




The problem is more common with electronics that are sealed in boxes with regular silicone. The solder and copper are more prone to react with the fumes released by the silicone as it cures. Used in an open automotive environment, the gases can escape. Maybe the problem is inconsistencies when applying the silicone that create air pockets under the cured silicone "skin" leading to corrosion? Maybe you don't apply the silicone excessively thick and you lay a consistent enough bead that there aren't any voids created to encapsulate gases. All I know is I've seen window frames rotted out all around because a leaking window gasket was sealed with household silicone sealant. Though, there are other factors involved such as the alloys in the metal the car body was stamped from and the chemicals used in the production of the silicone itself, all of which may (and likely) have changed over time. I'd still rather play it safe and use purpose-made stuff. Common household silicone sealant isn't as stable in constant outdoor environments as automotive windshield adhesive.

I'm not picking on you iamdub - this was just the post I picked to reply to out of several...

Several have suggested a combination of thread locking compound and plastic washer/cap/whatever. If you find a combination that works, great. Please share your success story after a few months in the weather. BUT...

Keep in mind that many plastics are severely embrittled by the chemical reaction that anaerobic thread locking compounds undergo as they cure. I've seen this multiple times, not the least of which at work, where we use Lexan (polycarbonate) panels to cover machinery openings. If an inexperienced assembler uses thread locking compound on any of the bolts, the panels crack within a couple of days, even with no stress applied.

I once repaired and re-calibrated a torque wrench where the handle retaining nut had come loose. I put Loctite on the nut "just to make sure". The next time I went to use the wrench, the handle (probably ABS or polystyrene) had cracked into dozens of pieces, just sitting in the toolbox drawer.

I can't say which plastics, under what environmental conditions, have an issue. And as iamdub pointed out, what happens in open air may be different than in an enclosed space with little or no ventilation. But I would recommend either using something else to seal the threads, or at least keep an eye on the plugs to make sure they don't crack.
 
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07Burb

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just made an appointment to get my new TPMS sensors installed on Friday morning. That light on the dash is driving me bonkers and it's time to make it go away. It better stay away for a while!! LOL

[rant]
The TPMS bullcrap is one my bigger annoyances with the newer cars/trucks. I wish there was a way to tune the system out. I hate it and it's useless to me.
[/rant]
 

Rocket Man

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just made an appointment to get my new TPMS sensors installed on Friday morning. That light on the dash is driving me bonkers and it's time to make it go away. It better stay away for a while!! LOL

[rant]
The TPMS bullcrap is one my bigger annoyances with the newer cars/trucks. I wish there was a way to tune the system out. I hate it and it's useless to me.
[/rant]
Read this thread. It seems there is a module that (so far) works to spoof the system.
https://www.tahoeyukonforum.com/threads/antennas-sticking-outa-my-tires.112927/
 

89Suburban

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just made an appointment to get my new TPMS sensors installed on Friday morning. That light on the dash is driving me bonkers and it's time to make it go away. It better stay away for a while!! LOL

[rant]
The TPMS bullcrap is one my bigger annoyances with the newer cars/trucks. I wish there was a way to tune the system out. I hate it and it's useless to me.
[/rant]


I thought you needed to spend that money on an AC compressor for the Dually?? :confused:o_O Phuck TPMS things... :nono:
 

07Burb

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I thought you needed to spend that money on an AC compressor for the Dually?? :confused:o_O Phuck TPMS things... :nono:
Not gonna worry about the dually AC til the Spring. I can fight through the lack of AC in the dually for a couple more weeks :)
 

swathdiver

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Met up with a fellow member today @dross99_si and attempted to find an emissions leak. Turns out the Tech-2 wanted the engine temp below 158 and that wasn't happening under today's Florida sun, even in the morning after a short drive. So instead we poked around the computer system and shot the breeze until next time. We're both chasing a P0442, very small evap system leak. The Tech-2 can be used to eliminate one portion of the system but I really need to make or buy a smoke generator and do a visual search.

Andy's 2007 Tahoe is one of the cleanest and well maintained trucks I've seen.

Oh, for you guys with Tech-2 and 2007 or 2008 trucks, where can you see the Fuel Pump Module or the pressure and such? Mine (2009) has a dedicated menu but did not see it on the 2007 and poked around a while and still couldn't find it.
 

iamdub

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I'm not picking on you iamdub - this was just the post I picked to reply to out of several...

Several have suggested a combination of thread locking compound and plastic washer/cap/whatever. If you find a combination that works, great. Please share your success story after a few months in the weather. BUT...

Keep in mind that many plastics are severely embrittled by the chemical reaction that anaerobic thread locking compounds undergo as they cure. I've seen this multiple times, not the least of which at work, where we use Lexan (polycarbonate) panels to cover machinery openings. If an inexperienced assembler uses thread locking compound on any of the bolts, the panels crack within a couple of days, even with no stress applied.

I once repaired and re-calibrated a torque wrench where the handle retaining nut had come loose. I put Loctite on the nut "just to make sure". The next time I went to use the wrench, the handle (probably ABS or polystyrene) had cracked into dozens of pieces, just sitting in the toolbox drawer.

I can't say which plastics, under what environmental conditions, have an issue. And as iamdub pointed out, what happens in open air may be different than in an enclosed space with little or no ventilation. But I would recommend either using something else to seal the threads, or at least keep an eye on the plugs to make sure they don't crack.

No offense taken! We should all welcome input from all perspectives, agreeing or not. Publicly hashing out our ideas is how we learn.

I actually never considered how the various compounds I planned to use would react with one another or with the nylon caps. I just shared what I've experienced with the silicone and metal corrosion (by the way, the windshield stuff is urethane, not butyl). Knowledge is power and now we will know to think twice if securing screws into plastic because there may be an adverse reaction.

I wasn't planning on using a thread locker, but a thread sealer. Yes, still, the material and chemical compatibilities should be considered.

Since the push-in rivet/"Christmas tree" idea, I'm nixing the set screws and aiming for using just the rivets/caps (after base coat and clear coat) and the windshield adhesive. I know many plastic clips used to locate and hold weatherstripping and trim around windshields are made of nylon. So I feel confident the auto body paint, nylon rivets/caps and adhesive will play well together. I'm getting a bulk of the caps so I'll have plenty to experiment with should it not go as planned. My only real concern is to not use anything that will corrode the car body itself and I think I have that under control since I'm using materials already commonly used together on cars.
 

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