Why does my new windshield leak?

[cwilkie]

I purchased a new windshield, weather stripping, and windshield trim. After getting it installed it leaks in a few places. Before it was the original glass and weather stripping without the trim. Is there a trick to getting the glass installed properly? Is there higher quality weather stripping out there? Or do I need to not use the trim? Please let me know what you guys think because every time it rains I get water all over my new interior.

[JimKshortstep4x4]

Your local glass shop should be able to seal it for you. They use compressed air at the shop near me to find where the water is coming in and then use a special sealant gun to seal the leak.

The top outer edges of the seal is where I have seen most leaks on these windshields.

Jim

[cdowns]

i'm not understanding what you did// there are 2different gaskets one for trimone without trim// i've never seen the trim cause a leak/

/did you clean the windshield channel real good before install?did you use plenty of lube on the gasket during install to aid in seating the gasket? where exactly is the leak? have you tried reseating the gasket at suspected leak areas?

[foosed]

i had a new windshield put in my 72 and it also leaked so i brought it back in and they put a sealant around the whole windshield

[cwilkie]

I have the the weatherstrip with the groove for the trim. I cleaned the glass and rubber before it was installed. After it was installed it seemed like the rubber was too small for the glass since the rubber didn't look like it covered equal amounts on the driver side. It leaks from the bottom on the driver and passenger sides. Are there better quality weatherstripping out there? It's really frustrating.

[JimKshortstep4x4]

The water will usually enter at the top outer edges and then it exits at the bottom. Trim or no trim usually does not make a difference. The Service Manual does suggest sealing the top outside corners.

I am not sure who has the best seals. I got the last one from GMC Pauls and it worked well.

Jim

[leddzepp]

I have heard that Precision makes the best windshield gaskets.

[unclewatts]

I don't know from personal experience, but I have read a lot of threads about this problem. What it all seems to come down to that a lot of different aftermarket companies sell really crappy windshield gaskets and the best one to buy is Precision. Hope this helps.

[sellersrodshop]

precision is better than some but still not anything to brag about. i went thru three precision gaskets before i got one to fit properly. the first two were too long & bunched up & the glass wouldn't go in. the third had edges that looked like they were trimmed by a guy with a bad hangover. i installed auto glass for over 20 years & if i had a choice, i always recommended steele rubber. they are little more pricey than the imported stuff, but well worth the price for the quality you will receive.

www.steelerubber.com

['68 C-20]

I don't know if this will help or not, but I had a windshield leak, or so I thought.

Two weeks ago I happen to pull the cowel off and noticed a small seam under the cowel about 3 inches below the windshield. It is part of the cab manufacturing and was sealed with a "rubber" sealent that looked like it was hand applied. The "Rubber" had shrunk and cracked. I climed under the dash with a light and sure enough I could not see daylight, but I could see a rust spot where the water was running in. I sealed it with some clear RTV and pushed it into the seam with me thumb, no more leak.

[ChevLoRay]

Originally Posted by '68 C-20

I sealed it with some clear RTV and pushed it into the seam with me thumb, no more leak.

Make sure you use an automotive grade of RTV. There's an industrial grade that will cause rust to form and it will be some time down the road before you know. Trust me on this. Here's what you can expect (over time) if the RTV isn't automotive-grade. This is where the wiper motor was installed until it fell out one rainy morning. P.O. had put the RTV around the mounting bolts, thinking he was addressing water leaking into the cab. I have more pix. The damage gets worse. I'll spare you.

['68 C-20]

Originally Posted by ChevLoRay

Make sure you use an automotive grade of RTV. There's an industrial grade that will cause rust to form and it will be some time down the road before you know. Trust me on this. Here's what you can expect (over time) if the RTV isn't automotive-grade. This is where the wiper motor was installed until it fell out one rainy morning. P.O. had put the RTV around the mounting bolts, thinking he was addressing water leaking into the cab. I have more pix. The damage gets worse. I'll spare you.

Holy Oxidization Batman! What a shame, real hard to repair too.

I have never heard or seen that before. I will have the cowel off again this fall, it easy and cheap enought to scrape out the RTV and re-apply. I used the Dow-Corning 732.

Thanks for the tip!

[ChevLoRay]

I have one more pix I will share. Non-automotive RTV, like the white stuff sold under the GE name (and others) was used where I worked to post operating instructions and other info onto these vertical steel columns in the buildings. Some posting were safety, some not. Anyway, we'd make an issue of getting enough on the back of the laminated sheets to be sure they'd stick. When it came time to update the info, we'd tug and pull 'em off of the columns and there was always rust behind the RTV.

Here's a pic of my firewall. P.O. used RTV to seal up what he thought was the bad spot. Problem is, he also created a dam that held any liquid that fell or thawed and now my HVAC area is toast around where the AC unit mounted. At least the gasket for the HVAC unit was good and didn't let any water accumulate behind it. I'm gonna end up with an aftermarket HVAC unit, when all is said and done.

Look and weep:

[Classic Heartbeat]

I would stay clear away from any RTV or silicone product what so ever. All silicone atracts water and will eventualy do what it has done to ChevLoRay's cab. Using the proper gaskets when installing the wiper motor (no other sealer needed) and automotive seam sealer where overlaps are is the only way to go. WES

['68 C-20]

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