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Truck windshield leaks!

654 Views 15 Replies 8 Participants Last post by  N2 Tractors
My old 1990 gmc s15 has a leak from I assume windshield gasket. I tried some silicone stuff from ace no luck. When I talked to windshield people they think it's probably all rusted under the seal or gasket. When it rains it drips in from headliner by windshield. Any ideas what I could try? Flex seal spray an option. Appearance not huge concern. Thanks.


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The roof on my '06 liberty rusted from the windshield back towards where the roof rack starts. Water would flow down the a-pillar, fill the footwell and generally make a mess. Window flashing tape works amazingly well. Will not come off and seals very well. Looks completely *******, but its my beater and not much longer for on-road service.
I’d think a tube of paintable polyurethane caulking would be a good sealer if you can determine where the leak is. Might pull the windshield to find the leak.
I’m afraid once the gasket starts leaking that’s it. The windshield has to come out and the metal edge around repaired. Once it rusts it loses its ability to seal. You want to fix it right anyway to stop the rust. Good news is its relatively easy. If I can pop that windshield out and fix it anyone can. Mine was an ‘86 so not sure if the gasket is exactly the same but I think so.
Flexseal tape and a visor...might work if you can't get the windshield out without destroying the seal. Is the seal still available?
I'm not 100% sure on availability see more pop up for rear window and doors.
If it’s like mine I re-used the seal as it was fine. Just the rust behind it making it leak. Depends on how long you want to hang onto it. Definitely some high quality sealants that will tighten it up for now.
Windshield on s-10 is glued in with butyl. It would have to be cut out. It probably has a hole rusted through under the trim piece. Trim piece could be removed and maybe able to find hole and seal with a good quality caulk.
Thanks I'll check it out. Be nice if the weather would straighten out to get outside and do something in the warm sunshine!
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I caught a break from the rain today :)
I really want to just spray it with flex seal and see what happens for now
Flex seal and some rear shocks and it’ll be better than new
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The ol girl didn't like being loaded down with mulch!
I had a leak like you do - mine was on a GMC box truck. I used an architectural caulk - Eucolastic 1NS - a polyurethane caulk that is incredibly tough when cured. Cost was about $8 a tube at a building supply yard. I applied the caulk along the top edge of the rubber seal all the way across the windshield - where the rubber meets the metal of the cab. I stopped applying the caulk where the seal bends down (water does not usually flow uphill).
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Thanks. I might have to check it out if I can find it. Problem might be all the stuff I've already globbed on there!🤣
This is the stuff right here. Get it at just about any big box store. Loctite PL S40 it comes in white, tan and black iirc.

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