Let's talk about grommets!

[SadRobot]

Around 2 years ago I took my Jeep to a shop and they drilled a hole in my firewall. The ran a bunch of switch wiring and air locker lines through it, no grommet. I discovered this about a year ago when I re-routed my switches and air locker lines.

I decided to re-use that hole since it's there now to run my antenna wire through the engine bay to mount. It's been fine for a year or so but really there should be a grommet in there so that brings me to today.

The antenna wire has these connectors on the ends. I don't believe I can separate the wire from these although I could be wrong on that.

So whatever grommet I use this black smaller end has to fit through.

This is the grommet kit I own already.

The closed grommets are too big but I could buy ones that fit the hole, slice a large vertical line into it and push the black connector end through.

Or I combined 2 grommets, sliced the side and that seems to hold fine. Are there any issues with the way I did this? Is the closed grommet with a slice a better idea?

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[SadRobot]

Well in this moment it's coming through a grommet that is jammed inside another grommet. I guess my question is this sealed enough? I feel like using a closed grommet with a slice is also going to not be 100% sealed either.

The closed grommets seem to be made with a different or thinner material. In a fire scenario those are going to melt. I know this for..... reasons.

 

[jaymz]

The best option is to use a grommet with an OD to match the hole, and an ID to match the cable. Cut it, slip it over the cable and then stuff it in the hole. If it's the right size it'll be a tight fit and won't leak.

The "grommet in a grommet" works, but the inside one will likely work it's way out at some point unless you use some sort of adhesive to bond the two together.

 

[SadRobot]

The best option is to use a grommet with an OD to match the hole, and an ID to match the cable. Cut it, slip it over the cable and then stuff it in the hole. If it's the right size it'll be a tight fit and won't leak.

The "grommet in a grommet" works, but the inside one will likely work it's way out at some point unless you use some sort of adhesive to bond the two together.

So to clarify I had the correct idea that it's better to slice a hole in the grommet and slip over as opposed to trying to slip the larger connect end through a bigger hole I have to make in one of the closed grommets?

So I need to find a grommet that is OD 5/8" with an ID of 1/4"?

Edit: I think I found it here!

 

[angrykitty]

So to clarify I had the correct idea that it's better to slice a hole in the grommet and slip over as opposed to trying to slip the larger connect end through a bigger hole I have to make in one of the closed grommets?

So I need to find a grommet that is OD 5/8" with an ID of 1/4"?

Nerd to the rescue!!!

Inside Diameter

Outside Diameter

Since inside hole could be measured many ways; radius, circumference, diameter, area, volume…. Any other measurements I’m missing?

 

[Terrymo]

 

[SadRobot]

Just found exactly what I need. $25 with shipping and tax. Comes in a pack of 100 unfortunately. Wish I could just buy 1.

https://www.imperialsupplies.com/item/9115955

 

[Terrymo]

Just found exactly what I need. $25 with shipping and tax. Comes in a pack of 100 unfortunately. Wish I could just buy 1.

https://www.imperialsupplies.com/item/9115955

Will these on Amazon work? Next day delivery with Prime
Bore Diameter: 1/4"
Groove Width: 1/16"
Groove Diameter: 7/16"
Outside Diameter: 5/8"
Overall Thickness: 3/16"
https://www.amazon.com/Rubber-Gromm...98b9ce&ref_=pd_hp_d_atf_ci_mcx_mr_ca_hp_atf_d

 

[THAW]

Also consider adding a drip loop. But be mindful of the minimum bend radius of antenna wires.

 

[SadRobot]

Will these on Amazon work? Next day delivery with Prime
Bore Diameter: 1/4"
Groove Width: 1/16"
Groove Diameter: 7/16"
Outside Diameter: 5/8"
Overall Thickness: 3/16"
https://www.amazon.com/Rubber-Grommets-Bore-Diameter-D/dp/B0040CRRH8/?_encoding=UTF8&pd_rd_w=R0uzl&content-id=amzn1.sym.f8fbf489-893c-481c-b7fa-18e0b0ecaa0c:amzn1.symc.a68f4ca3-28dc-4388-a2cf-24672c480d8f&pf_rd_p=f8fbf489-893c-481c-b7fa-18e0b0ecaa0c&pf_rd_r=MA3SXK6MZ01QQFR5EYSJ&pd_rd_wg=UzV6N&pd_rd_r=57024f30-5783-4ba6-9b60-08885398b9ce&ref_=pd_hp_d_atf_ci_mcx_mr_ca_hp_atf_d

Yes I think that would. Thanks for the link!

 

[muskynut]

Seal it with black silicone sealant. Not difficult.

 

[Wain970]

Around 2 years ago I took my Jeep to a shop and they drilled a hole in my firewall. The ran a bunch of switch wiring and air locker lines through it, no grommet. I discovered this about a year ago when I re-routed my switches and air locker lines.

I decided to re-use that hole since it's there now to run my antenna wire through the engine bay to mount. It's been fine for a year or so but really there should be a grommet in there so that brings me to today.

The antenna wire has these connectors on the ends. I don't believe I can separate the wire from these although I could be wrong on that.

So whatever grommet I use this black smaller end has to fit through.

This is the grommet kit I own already.

The closed grommets are too big but I could buy ones that fit the hole, slice a large vertical line into it and push the black connector end through.

Or I combined 2 grommets, sliced the side and that seems to hold fine. Are there any issues with the way I did this? Is the closed grommet with a slice a better idea?

Well in this moment it's coming through a grommet that is jammed inside another grommet. I guess my question is this sealed enough? I feel like using a closed grommet with a slice is also going to not be 100% sealed either.

The closed grommets seem to be made with a different or thinner material. In a fire scenario those are going to melt. I know this for..... reasons.

Do you have a picture of where this is coming through on the other side? I’m trying to decide where to drill a hole for a Lasfit hood latch lock kit’s air lines on a JL Manual transmission. I was already thinking about this spot but I’m not sure exactly where it will be in the footwell. If you are still looking for a better grommet search “Seaview cable gland” on Amazon it would have to be attached to the firewall with screws or bolts, it’s made for boats and expensive but totally waterproof. Saw it on a YouTube video used on a JL hardtop roof for wiring to a light setup. Or you could use a “Fastronix weatherproof grommet” made for firewall pass through and inexpensive but would probably still require some silicone sealant to make it totally waterproof.

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