Factory roof rack install - I don't have the black gaskets, what can I use to make some?

[Giant Rock]

Recently purchased a factory roof rack for my 1990 Suburban. I have learned from the forum that different years were installed in different ways i.e some years had nut inserts and some years used sheet metal screws. The roof rack uses black plastic (or maybe rubber?) gaskets at the attachment points, as see in this image:

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The rack I purchased unfortunately did not come with these gaskets. Does anyone have a recommendation on something I could use to make some? I was thinking about a sheet of rubber perhaps that I would cut to fit, but I really don't know.

Lastly, here's a fun pic, thanks for reading.

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[skysurfer]

I was missing a couple of them and made some from material I got at Ace Hardware. It wasn't the right color but it's not something you'll notice after installation. This stuff was the right thickness and easy to work with. I tried to find the Ace stock number online but couldn't. This came as a small sheet, maybe 6"x6" or 6"x8", packaged in the typical red/white blister packs that Ace uses to package everything. I found it in the plumbing & bath section. I kept my eyes open for anyone on GMSB parting out a burb and eventually got the correct pads.

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[Snoots]

Use an old truck tire inner-tube.

 

[Giant Rock]

I was missing a couple of them and made some from material I got at Ace Hardware. It wasn't the right color but it's not something you'll notice after installation. This stuff was the right thickness and easy to work with. I tried to find the Ace stock number online but couldn't. This came as a small sheet, maybe 6"x6" or 6"x8", packaged in the typical red/white blister packs that Ace uses to package everything. I found it in the plumbing & bath section. I kept my eyes open for anyone on GMSB parting out a burb and eventually got the correct pads.

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Oh cool that looks exactly what I am going for. Did you install the rack with sheet metal screws?

 

[skysurfer]

Oh cool that looks exactly what I am going for. Did you install the rack with sheet metal screws?

That's the strange thing, this was a factory installed rack and there are two types of hardware used. The forward-most screw on each side, along with the most-rearward screw on each side, are 8-32 n.c. machine screws. So four of those total. All the other screws are what appear to be #10 x 1/2" sheet metal screws. I know this is is the oem setup because I'm the second owner and the original owner was a lady that didn't touch anything. If your adding a rack that wasn't on there originally, just go with something like the shorter screw in the picture.

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[Crispy]

I cant add to what @skysurfer posted, spot on. My burb didnt come with a roof rack either. The OEM gaskets are a rigid plastic and sheet metal screws are used as previously mentioned. When my rack was pulled the screws seemed to be dry, meaning no RTV or other thread sealer was used. When I installed mine I added a drop on each screw and I dont know if its needed but it made me feel better about the install.

 

[Giant Rock]

That's the strange thing, this was a factory installed rack and there are two types of hardware used. The forward-most screw on each side, along with the most-rearward screw on each side, are 8-32 n.c. machine screws. So four of those total. All the other screws are what appear to be #10 x 1/2" sheet metal screws. I know this is is the oem setup because I'm the second owner and the original owner was a lady that didn't touch anything. If your adding a rack that wasn't on there originally, just go with something like the shorter screw in the picture.

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Sweet thanks for the info very helpful. I'm a complete noob so forgive this next question...if I go with the shorter screw in the picture (that's called a sheet metal screw right?) do I need to drill pilot holes first or are they self tapping? How much smaller does the pilot hole need to be?

 

[Crispy]

I laid down painters tape where the screws would be.
Placed the rack in as close to stock position that I could find using photos on the web.
Used a marker to mark screw holes.
Removed rack.
Drilled pilot holes.
Removed tape.
Installed rack.

The paint on my burb is pretty nice and I didnt want to chance the screw slipping.

 

[skysurfer]

I would drill pilot holes first. You can buy self-tapping screws but they’re sort of a “wham bam thank you mam” approach to repairs and not something I’d use on a painted surface. Easiest way to figure out what size drill to use is to hold a screw up to the light with one hand and with your other hand hold a drill bit in front of the threads. You should pick a drill that comes close to the size of the screw’s body but doesn’t cover any of the threads as you’re looking at it. If you’re not sure, step down one size. As for the screws, just look for something similar to what I posted above, but spend a little extra for stainless screws. Just a small dab of 100% silicone caulk on the pilot hole and screw would also be a good idea.

Edit: Really like Crispy’s idea of using tape.

 

[Giant Rock]

Awesome you guys thanks for the detailed info, very helpful! Last question: What sealant do you think is better for the sheet metal screws between these two options?

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[Snoots]

RTV

 

[Giant Rock]

RTV

Cool thanks!