Body molding/trim for roof

[iamdub]

Thanks for the pics and info!

I'm gonna try to go to the scrap yard tomorrow and experiment on a NNBS SUV. I also bought some rubbing compound and new bonnet for the DA polisher. How well the footprints clean up will determine what size molding I use and the results of drilling out the Rivnuts will determine if I use my painted tree rivets and/or if I'll need to recess the underside of the molding.

To be continued...

 

[SRQYukon]

Some reasons I did not drill out the rivnuts when I did mine: 1) They stick up rather high, and it seems risky to drill without damaging the roof and causing a leak; 2) didn't want to fill the holes or have to paint any bare metal; and 3) I wanted to have the option of putting the rack back on in the future if I sell my truck. If your planning to never put it back on you can drill or grind everything flush so long as you don't cut through the sheet metal.

 

[iamdub]

Some reasons I did not drill out the rivnuts when I did mine: 1) They stick up rather high, and it seems risky to drill without damaging the roof and causing a leak; 2) didn't want to fill the holes or have to paint any bare metal; and 3) I wanted to have the option of putting the rack back on in the future if I sell my truck. If your planning to never put it back on you can drill or grind everything flush so long as you don't cut through the sheet metal.

All points I've pondered. I believe that using molding with recesses for the Nutsert flanges will be my final decision. But I still wanna experiment on the roof of a wrecked car at the scrap yard just for the knowledge and to slice on a NNBS.

My thoughts on drilling off the flanges is to screw in a set screw before I drill to keep the shavings out. After the flange is gone, I'd clean the hole with compressed air, squirt some oil on the threads then back out the set screw to "re-tap" the end of the thread. If I ever wanted to reinstall the rack, I could use washers the same thickness as the Nutsert flange and the same urethane sealant I'll be using under the painted tree rivets.

The tree rivets would be the cheapest route and I already have them painted. But, a strip of molding would look better than even the nearly-flat painted "dots" and it's non-damaging. Sometimes (or usually?) the best option isn't always the cheapest option.

 

[iamdub]

If anyone is wondering, the Nutserts on a NNBS are definitely NOT blind nor do they tie into anything structural.

I found an '07 Avalanche (Graystone, coincidentally) with the roof rack already removed. I pulled down the headliner near the driver's door and this is what I saw:



That's sunlight shining through the surface-rusted threads.


I already had my answer but I brought my cordless grinder and I was gonna use it!

I ground the flange almost all the way through to see if I could do it without damaging the roof metal:




After prying the flange off with a small flathead screwdriver, the rest of the Nutsert fell inside, leaving this hexagonal hole:




So, it's an all or nothing deal. Make the roof rack removal permanent or cover the Nutserts with molding. Looks like I'll be ordering molding in the future.

 

[wjburken]

If anyone is wondering, the Nutserts on a NNBS are definitely NOT blind nor do they tie into anything structural.

I found an '07 Avalanche (Graystone, coincidentally) with the roof rack already removed. I pulled down the headliner near the driver's door and this is what I saw:

View attachment 237275

That's sunlight shining through the surface-rusted threads.


I already had my answer but I brought my cordless grinder and I was gonna use it!

I ground the flange almost all the way through to see if I could do it without damaging the roof metal:

View attachment 237276


After prying the flange off with a small flathead screwdriver, the rest of the Nutsert fell inside, leaving this hexagonal hole:

View attachment 237277


So, it's an all or nothing deal. Make the roof rack removal permanent or cover the Nutserts with molding. Looks like I'll be ordering molding in the future.

Thanks for sharing your learnings. That definitely clears things up.

That bit of information will come in handy for folks trying to track down water leaks as well as I am assuming that although the nutsert was crimped pretty tight that it’s not necessarily a water tight joint.

 

[iamdub]

Thanks for sharing your learnings. That definitely eats things up.

That bit of information will come in handy for folks trying to track down water leaks as well as I am assuming that although the nutsert was crimped pretty tight that it’s not necessarily a water tight joint.

I can see plenty of potential for leaks in this setup. A roof rack that gets used often or just hit a bit too hard could loosen up a Nutsert just slightly, making it no longer watertight. Over time, a little moisture collecting near the flange and leaking in could corrode and eat away the roof skin, causing a visible leak (wet headliner) and it's all down hill from there.

I'll be using set screws with thread sealant and capping that with windshield adhesive (regular silicone sealant can corrode metal) and maybe even smear a tiny layer of the adhesive around the Nutsert flange where it meets the roof before I cover it all with the molding.

 

[gooffeyguy]

Odd that it doesn't go into a support or supported area of some sort. You would think since the rack can hold like 200lbs plus any extra wind resistance put on it at speed.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[BG1988]

Not what you’re looking for exactly, but the hybrid looks like it’s got something bolted over the roof rail holes to me. Like mini roof rails?


Mine has some thick rubber plugs over the holes (I’ve seen some ssv’s like mine and other where they never had rails).

there is no holes on the roof for me besides the shark tail and sunroof

it also has the standard "Crumple Zones"

 

[iamdub]

Odd that it doesn't go into a support or supported area of some sort. You would think since the rack can hold like 200lbs plus any extra wind resistance put on it at speed.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

I was quite surprised as well. The roof skin is adhered to and supported up off of that inner boxed frame with the black foam stuff you see in the first pic. I could flex the roof slightly by pressing on it. Judging by how hard I had to press on that one spot for it to flex enough to be seen, I'd say it could easily support 100 lbs. on that one side if all three points were bearing the load. So, 200 lbs. evenly distributed among the whole rack seems realistic.

 

[89Suburban]

If anyone is wondering, the Nutserts on a NNBS are definitely NOT blind nor do they tie into anything structural.

I found an '07 Avalanche (Graystone, coincidentally) with the roof rack already removed. I pulled down the headliner near the driver's door and this is what I saw:

View attachment 237275

That's sunlight shining through the surface-rusted threads.


I already had my answer but I brought my cordless grinder and I was gonna use it!

I ground the flange almost all the way through to see if I could do it without damaging the roof metal:

View attachment 237276


After prying the flange off with a small flathead screwdriver, the rest of the Nutsert fell inside, leaving this hexagonal hole:

View attachment 237277


So, it's an all or nothing deal. Make the roof rack removal permanent or cover the Nutserts with molding. Looks like I'll be ordering molding in the future.

Great job sharing this with us!!!! Thanks!!!