Recurring windshield leak

General information about the first-generation Nissan Maxima in the US. What was the Datsun 810 became the luxury leader Maxima in the US in 1981.

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goglio704
Posts:726
Joined:15 years ago
Location:East Tennessee
Recurring windshield leak

#1

Post by goglio704 » 13 years ago

Mom's White '83 has a windshield leak again. It had a leak about 2 years ago. At that time I pulled the trim and cut away some of the polyurethane and basically caulked it with windshield polyurethane. The glass was somewhat loose so I gently worked the glass in and out to try to get the sealer to penetrate. That part seems to have worked, because the glass is not loose in those areas this time.

I think the scenario this time is a little different. Above the glass is a J shaped plastic channel which acts as a retainer for the trim. The upper, long side of the J was secured with some kind of double stick tape. About four inches of this tape was no longer adhered. Rust set up in that area. Moisture also got under the channel and set up some rust. It isn't rusted through, but I think the sealer lost its grip on the rusted metal and that is the new leak.

I didn't take the J channel out last time, but I have this time. With that channel gone and the sealer above the glass cut away, I have a 3/8" gap between the top of the glass and the roof. I got in there and scraped and sanded. I have treated the area with rust converter. I'm going to reinstall the J channel with polyurethane unless someone has a better idea and reseal the top of the windshield. Hope this works. If it leaks again, I'll pull the glass out and really do it right. I'm trying to avoid taking the glass out. Unlike the back glass, I don't think the windshield has any custom rubber parts that I'd have to find. It looks like a standard "kit" as the glass guy called it last time I had glass work done on a car.

I'm trying to avoid the expense and hassle of having "professional" glass work done. It's not that I'm unwilling to pay a professional, I just have spotty luck hiring stuff done. :roll:
Matt B.

83 Maxima Sedan, LD28, 5 speed, white, 130k miles. My original Maxima.
83 Maxima Sedan converted from gasser, LD28, 5 speed, 2 tone blue, 230k miles
82 Maxima Sedan, LD28, 3 speed auto, 2 tone Gray/Silver, 140k miles
81 810 Sedan, LD28, 3 speed auto, rust, rust, and more rust!

2005 Jeep Liberty CRD

rlaggren
Posts:541
Joined:13 years ago
Location:San Francisco

#2

Post by rlaggren » 13 years ago

Sounds like you have a real good chance to fix it. Two thoughts which sort of oppose each other:

1) Try to fill the spaces so as to eliminate standing water. (You probably figured to do this.)

2) Caulking has to allow the two sides of a joint to move, and do it w/out losing its grip. This seems clear. What is sometime forgotten is that the thicker the bead of caulk, the less it will flex (the more force it requires to get it to stretch or shrink as required). Think how a thin rubber band stretches easily over a wide range while a really fat rubber band is much harder to stretch and doesn't strech as far. Thus for larger gaps, caulking needs to be installed over some kind of filler material so it forms a thin layer instead of a fat bead. The fill should either NOT stick to the caulk or the filler material needs to have great flexibility so it never restrains the caulk from moving. Filler rods of open cell foam are sold for this purpose. When installed this way, the caulk forms a thin membrane over the top of the joint and this thin film stretches and moves easily w/out disconnecting at the edges. The disconnecting at the edges part is where most thick beads of caulk fail because the force needed to stretch the fat bead is greater than the caulk's adherance to the sides of the joint.

Having said that, I'm not sure how I'd approach a windshield w/really big gaps to fill. Maybe by doing it in 2 or more steps with drying times between; layering the stuff in hopes that the different layers would slide over each other a little and provide the needed flexibility.

This seems the likely reason that the big glass on vehicles is often set in designer rubber flashing, not just caulked in. FWIW, when I got a quote from a windshield chain of less than $300 for an 82Maxi wagon windshield with a lifetime warrantee. There are no "grey hairs" in that outfit, just operaters w/a database and mobile installation vans, but I did have them double check their info and they said the glass was immediately available and full warrantee applied. Don't know what system they'd use to ensure a seal.

Rufus

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