1969 windshield install

[Greg L.]

Does anyone know how thick the four rubber spacers should be that hold the windshield off of it's frame?

What's the proper sealant to use....standard black urethane windshield sealant that comes in a tube?

[Alan S.]

Re: 1969 windshield install

Hi Greg,
On my 71 I used a foam rubber strip from a Toyota windshield to simulate the foam rubber 'damming strip' that Chevrolet used. I then used 3M, Windo-Weld Ribbon Sealer, 1/4" x 15', #08610.
I did some testing and found that the foam + ribbon sealer held the windshield a proper distance from the windshield frame so that the SS windshield trim could be 'snug' against the windshield when installed as intended. So I didn't use the rubber spacers.
I used a tube of sealer around the perimeter after I installed the windshield just to be sure.
Because I had been looking for a Chevrolet damming strip for years, I was a bit bummed when I had to resort to a Toyota strip. I want to any old Chevy Dealer I could find and asked because the strip was part of the windshield replacement kit that the parts department sold years ago. Most parts guys had no idea what I was asking about, the old guys knew what I meant, would think they had 1 in the 'back someplace', but could never find it.
I hated to give up but it finally came to a point the windshield had to go in. I hope you're not as wacko as I am.
Regards,
Alan

[Greg L.]

Re: 1969 windshield install

Oh I'm wacko alright! Just spent several hours driving around town looking for some GE 1895 bulbs because I wanted new ones behind that dash and didn't want Chinese ones. Finally got some at two different places and when I get home I see that they are made in Hungary. Do we make anything here anymore????

I'll have to look into this windshield thing for a bit. I just assumed that they were all glued in, then I read an old thread about those 4 spaces(which I now have a dimension for) and now I'm getting the impresion that a rubber strip sealed the windshield.

Does anyone know if there is a way to tell on the judging field if the "correct" seal was used or is just spacing the windshield of the frame so that the trim touches it and then use common window sealant good enough?

[Alan S.]

Re: 1969 windshield install

Hi Greg,
Once you learn what to look for you can tell in an instant from the exterior of the car whether an original type damming strip is still in place. My belief is that you should only see the damming strip, no actual sealer at all.
The Chassis Service Manual describes the installation procedure and the damming strip. The strip is run around the perimeter of the windshield 1/4" in from the windshield's edge. Then the sealer is run on that remaining 1/4" of glass. It does mention using the rubber spacers, BUT since I used a round bead strip caulk I didn't need to hold the windshield some distance from the windshield frame. I saved ALL the caulking and damming material from my car's original windshield installation and I've never found any hint that spacers were used on my 71.
Of all the things that drove me crazy on this car, the damming strip was the most frustrating because I really thought I'd find an old GM kit with the strip in it. Even though my windshield has been in for 3 years I still look for the strip anywhere I go. The crazy part is whether I'd change it now?!
Regards,
Alan

[Jack H.]

Re: 1969 windshield install

Most of the common sources for incandenscent lamps are or have gotten out of the business (pending legislation on use of compact flourscent + LED technology) which is why you see today's sources from either the Far East or the ex-Soviet block countries. It's a similar situation for vacuum tubes...

[Dino L.]

Re: 1969 windshield install

Any glass shop can provide you with foam dam tape or butyl tape as well as a tube of polyurethane.....These tapes come in several standard sizes....

[Greg L.]

Re: 1969 windshield install

Alan do you have a pic of what this damming strip looks like? I found the windshield installation section in the service manual but it makes no mention of a damming strip(1969 manual). The AIM does however show what looks to be a "U" shaped piece of "sealer" attached to the windshield so I'm wondering is this isn't the "damning strip"? What's the damming strip for anyways? To me it's just for looks or possibly to keep your hands from sticking to the actual caulking if you were cleaning the inside of the glass on a very hot summer day???

[Alan S.]

Re: 1969 windshield install

Hi Greg,
The damming strip was used to keep the sealer from oozing toward the center of the windshield as you thought. And as Dino posted, the modern damming strip is readily available in many sizes, shapes and material variations.
The RUB is that on the new strips the pressure sensitive adhesive is applied directly to the foam, or has a transparent carrier, while on my 71 the adhesive was actually applied to what appears to be a THIN linen strip and this strip was applied to the foam. Also, I've not found the proper shaped strip, so far.
The linen and adhesive have yellowed over the years (from the sun?) and this linen and adhesive is what you see on the two vertical sides of the windshield when you look in from the outside. On 71s you can't see it on the top because of the tint and on the bottom because of the way the windshield is coated to block out the part of the cowl it extends over.
In my 71 AIM it's shown on UPC1, Sheet F8, View B, Symbol#170. It's called... Seal Windshield Glass, 134 inches. Part #3926350.
My camera has been dropped, so I'm lost for new pictures right now. If you PM me your address I'll send you a tiny piece of the strip.
Regards,
Alan

PS: The only good part of all this is that I don't loose any sleep over it. The bad part is that there are less and less OLD Chevy Dealers for me to find.

[Greg L.]

Re: 1969 windshield install

Thanks Alan, I just sent you a PM.

Dino, I didn't realize that anyone still sold that butyl tape for windshields. I saw some of what looked like butyl tape of about 1/8" in a parts store not long ago and was going to see if they could get some 3/8" stuff but now I'll just try a glass shop.

[John H.]

Re: 1969 windshield install

Thanks Alan, I just sent you a PM.

Dino, I didn't realize that anyone still sold that butyl tape for windshields. I saw some of what looked like butyl tape of about 1/8" in a parts store not long ago and was going to see if they could get some 3/8" stuff but now I'll just try a glass shop.

You do NOT want to use the "butyl tape" to install the windshield; although it's available in 5/16" and 3/8" thicknesses, it's used by some aftermarket glass shops as a "quick-and-easy" band-aid substitute for the correct pumpable urethane adhesive (which is the current replacement technology for the original Thiokol pumpable adhesive the plant used). Butyl tape won't pass the MVSS windshield retention requirement, and with butyl tape, the windshield no longer contributes to the stiffness of the cowl structure.

The original installation used the adhesive "dam" to keep any "squeeze-out" of the pumpable adhesive from becoming visible inboard of the edges of the garnish moldings.

[Alan S.]

Re: 1969 windshield install

Hi John,
Your information and caution has made me realize I'm going to re- installing my windshield since I used the 3M installation kit with the butyl tape.
Perhaps by then I'll have found the damming strip.
Thanks very much!
Regards,
Alan

[Patrick H.]

Re: 1969 windshield install

Hi John,
Your information and caution has made me realize I'm going to re- installing my windshield since I used the 3M installation kit with the butyl tape.
Perhaps by then I'll have found the damming strip.
Thanks very much!
Regards,
Alan

Allegedly the damming strip is available through windshield/auto glass replacement companies. If you find a definitive source, please let us all know.

Patrick

[Greg L.]

Re: 1969 windshield install

Boy do I have a headache....

Seriously, I'll go back to my original idea which is to use whatever the local glass shop uses to install windshields. From what I remember comes in a caulking tube and I think it's urethane...

Once I get the damming strip sample from Al I'll see what I can find that resembles it and will for sure let you all know.

[Alan S.]

Re: 1969 windshield install

All,
This is the last.... for now.
The damming strip has a tiny 'key-way' cut into it for the Thiokol to extend into, (to help everything stay in place?), because the Thiokol doesn't/didn't bond to the damming strip.
There are a multitude of damming strips available. I've never found one close to the quarter-round shape of the original. It's that rounded shape that you can see as you look through the windshield.
Things are getting verrry blurrrry and dim. Over and out!
Regards,
Alan

STILL HAVING FUN PLAYING WITH AN OLD CAR.