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

[Doubeleive]

I fixed my cracks with JB Weld black plastic epoxy. You're supposed to mix the two parts 50/50, but I added an extra dab of one pf the two parts, I forget which. But, it cured to almost exactly the same color as the dash. I know yours is tan but I wanted to mention that for anyone with a black dash. Aside from color, the epoxy itself works wonders. If it were me, I'd cut a popsicle stick in half, apply epoxy to one side of each half and press them to the underside of the dash, spanning the crack like stitches. Might need to stuff a rag or newspaper underneath to lift and support it slightly if that closes the crack a little more. Let the eopxy cure over night, then reinstall the speaker with dense plastic foam glued to the magnet to support it. I'd have the foam thick enough so that it squishes just a tiny amount so that there's a slight bit of upward pressure. It'll settle over time and the upward pressure would essentially "zero out" so there'd be practically no force, up or down, on the center of the dash. It'd be supported, but not rigid.

That's a great idea I should have a small clamp that I could put on it overnight while it cures.

 

[Sam Harris]

Been eyeballing my cracked dash bouncing around for sooo long. The constant rattling is driving me crazy.

So I decided to investigate further and see if I can come up with some sort of support and why it is cracking. Of course the endless posts around the net and here on the TYF have that detailed to a "T".

I used a plastic panel tool and very carefully popped the 4 tabs on the center speaker cover to reveal the culprit of the 2 center speaker cracks.

1. Zero support in the center of the dash where it meets the front split.

2. Heavy ass Bose center speaker held in place by 2 screws.

3. Zero support on/around/under the Bose speaker.

The speaker is only held in in place with 2 x 7mm screw into the thread inserts. Very thin tabs to stabilize the speaker and dash in the center with no support.

So moving forward now that we have some details.

I am not interested in removing/replacing the dash at this point.

I've thought about some hot glue or quick epoxy around the tabs to secure them from completely separating from the dash.

Any thoughts about the extended cracks out from the cracked tabs where the screws go in place?

I thought about some hot glue/epoxy and a small bit of plastic under the existing cracks to keep them from opening up or spreading (unlikely to stop that from happening). Maybe some double sided foam gasket to keep the the gap between the 2 dash pieces from bouncing around so much.

I played the stereo without the center speaker and although not perfect, not even sure if the wife would notice. That would take the stress off the dash or test fit a piece of foam or something soft to absorb the bump under the magnet to fill in that gap behind the head unit and support the bottom of the speaker and dash.

Just figuring since I have that opening to work with a bit, to shore up the areas a bit. Not rigid, but flexible or shock absorbing for the dash.

Open to thoughts and input as I am spitballing here. Thx guys.

Speaker attached and cracks spidering out.


View attachment 240307


Speaker removed and can see the cracks.
View attachment 240308


You can see the cracks originating from the screw holes from the center speaker. Where those threaded insert tabs are x 2 the plastic has cracked where the tab is so the only thing holding it in place is the insert.

I can access that front left crack perhaps to glue and seal it together again, since both sides of the crack have already terminated. May not prevent a new crack originating from another but could at least join that crack back together.

The bottom crack maybe could stop it from advancing.

Just leaving the speaker out would relieve the stress of the center of the dash or as mentioned above something soft to take the weight of the magnet from hanging directly down.


Close ups inside the void. Looking forward.
View attachment 240311


Looking top down.
View attachment 240312

Man that’s bs..

 

[Fosscore]

That's a great idea I should have a small clamp that I could put on it overnight while it cures.

I concur and thanks for the "stitches" vision. Kind of the idea I was thinking about since I can access it through the speaker hole.

Anybody done anything with the cracks over by the passenger airbag or just not looked over that direction? lol

 

[Sam Harris]

I fixed my cracks with JB Weld black plastic epoxy. You're supposed to mix the two parts 50/50, but I added an extra dab of one pf the two parts, I forget which. But, it cured to almost exactly the same color as the dash. I know yours is tan but I wanted to mention that for anyone with a black dash. Aside from color, the epoxy itself works wonders. If it were me, I'd cut a popsicle stick in half, apply epoxy to one side of each half and press them to the underside of the dash, spanning the crack like stitches. Might need to stuff a rag or newspaper underneath to lift and support it slightly if that closes the crack a little more. Let the eopxy cure over night, then reinstall the speaker with dense plastic foam glued to the magnet to support it. I'd have the foam thick enough so that it squishes just a tiny amount so that there's a slight bit of upward pressure. It'll settle over time and the upward pressure would essentially "zero out" so there'd be practically no force, up or down, on the center of the dash. It'd be supported, but not rigid.

This

 

[Rocket Man]

I plastic welded my broken dash using hot staples that I melted into the plastic from underneath ( no center speaker to blame it on btw) and used 1/8” metal rods with epoxy spanning the cracked areas, reinstalled it and put everything back together. A week later a new crack appeared. I ended up replacing the dash with the supposed redesigned one and added my own reinforcing as well. My thoughts are that the design as well as the plastic is defective and once cracking starts it’s pretty much done, it will continue. The plastic on mine was pretty damn brittle.

 

[Fosscore]

Man that’s bs..

Yes it is man. Well chronicled with the NNBS. No doubt the NBS was IMHO far superior with some of these weak points...e.g. interior and exterior door handles, dash cracks, A/C buttons paint, etc...just a few things that even on my low mileage, late model NNBS have had happen.

Something about the NBS....

I plastic welded my broken dash using hot staples that I melted into the plastic from underneath ( no center speaker to blame it on btw) and used 1/8” metal rods with epoxy spanning the cracked areas, reinstalled it and put everything back together. A week later a new crack appeared. I ended up replacing the dash with the supposed redesigned one and added my own reinforcing as well. My thoughts are that the design as well as the plastic is defective and once cracking starts it’s pretty much done, it will continue. The plastic on mine was pretty damn brittle.

I remember you doing this Mark. I know...likley a Band Aid but maybe a good treatment for now since not ready to replace the whole damn dash.

 

[Doubeleive]

I concur and thanks for the "stitches" vision. Kind of the idea I was thinking about since I can access it through the speaker hole.

Anybody done anything with the cracks over by the passenger airbag or just not looked over that direction? lol

you could apply the same thing over in the airbag area, you would have to pull the passenger side airbag to get in there to clamp it

 

[Fosscore]

you could apply the same thing over in the airbag area the cover comes off just like the speaker grill only not as easy just use a plastic trim tool I took mine off to get to the passenger side hvac actuator, might have to move the airbag to get a clamp on it I don't remember how much space there was in there with the airbag in place.

Do you by chance remember where the clips were located? 4 clips in the corners or maybe 6 clips? Yeah I gingerly pried off the speaker cover as it is pretty much paper thin.

 

[Doubeleive]

Do you by chance remember where the clips were located? 4 clips in the corners or maybe 6 clips? Yeah I gingerly pried off the speaker cover as it is pretty much paper thin.

about 2minutes in you can see where the clips go, looking at this again I think you will have to pretty much do what I did I think the cover is attached to the airbag.

 

[lowh07]

Needs a bath but I like this pic