Rear glass sash rubber

K5Rob · Apr 20, 2025

Hey guys, tearing into my k5 tailgate, the rear glass sash is completely gone. I found a replacement and the rubber strip that holds the glass into the sash. Apparently you form the rubber around the glass and then press or gently tap the glass into the sash with a mallet. I am skeptical, especially since aftermarket stuff like this doesnt always fit well. Was wondering if maybe windshield polyurethane would be better or maybe a combination of both. What are your guys thoughts?

saltdog · Thursday at 6:53 AM

RTV works pretty good on both sides of that rubber, lubes it up, holds it in.

K5Rob · Thursday at 7:08 AM

saltdog said:
RTV works pretty good on both sides of that rubber, lubes it up, holds it in.

Thanks saltdog. My fear is the glass will pop out of the sash due to the older components and just the reputation the tailgates have for friction and not working well. I plan on going manual but its just not in the cards this year and i need it “functional” at least with a cordless drill to be able to do some work around the truck. I have the new sash here and am waiting on the rubber as it is backordered at the moment.

bucket · Thursday at 2:41 PM

K5Rob said:
Thanks saltdog. My fear is the glass will pop out of the sash due to the older components and just the reputation the tailgates have for friction and not working well. I plan on going manual but its just not in the cards this year and i need it “functional” at least with a cordless drill to be able to do some work around the truck. I have the new sash here and am waiting on the rubber as it is backordered at the moment.

I've used windshield urethane and it works really well. I believe it also helps keep the sash from rusting away because it doesn't collect debris and moisture like the original setup.

However, I do drill a bunch of 3/16" holes through the sash, to give the urethane more to bite onto.

Edelbrock · Thursday at 4:14 PM

Not sure if this is what your after, but I installed this on my K5 rear window and it works GREAT. Easy to install as well.

Link:

Amazon.com

saltdog · 2025-04-29T17:42:06-0400

@K5Rob Had same concerns too but its worked for me without issue for at least 6 years. Urethane is way more PIA to get out just sayin

K5Rob · 2025-04-29T17:45:39-0400

saltdog said:
@K5Rob Had same concerns too but its worked for me without issue for at least 6 years. Urethane is way more PIA to get out just sayin

Thanks. Do you think the RTV is helpful or just go with the rubber? I do have RTV on hand but not urethane and I know its expensive.

bucket · 2025-04-29T23:42:45-0400

I feel like my post went unnoticed, lol.

Urethane kills two birds with one stone. Not only does it hold the window to the sash permanently, but it also helps eliminate the reason that the sash rusted to begin with.

Yeah, RTV may work ok, but I wouldn't expect it to last as long as I plan on owning the rig. RTV is a sealer, not an adhesive. I'd rather spend the few extra dollars (ok, several extra dollars, lol) on a tube of urethane and never have to worry about it.

Again, if it's said that RTV has worked for you, I'm inclined to believe it. But personally, I'd want to know it's going to last. Redoing a failed previous repair is often a much bigger pain in the ass than doing it the right way to begin with.

Rear glass sash rubber

K5Rob

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