Two questions for the installation of back window

First there is not a forum for "windows" so I guess this is the most correct place for this question.

It has been almost three years that I cut the back window out of the car and now I want to put it back in. Before I put the window up into the attic I cleaned both sides real good. Now I don't know which way it goes back in.

First, Is the writing in the center of lower edge that reads "soft Ray" "Safety tempered" supposed to be read correctly? Or is it suppost to be backwards?

Second, What is the correct size of rubber bead do I need to use? 1/4", 5/16", or 3/8"?

One thing I learned today is how tough the back glass is. While I was test fitting the glass in the channel it sliped out of my hands and I ducked for cover only to find to it hit the car's floor with not even a chip. :shock: I did not even look until I checked my pants (if you know what I mean). :laugh:

 

I believe they should be readable from the outside.

 

Andy is correct. I buy the butyl window seal from AutoZone and use 5/16 or 3/8. Does not matter between the two since you will be compressing the seal and it will change diameter. While you have the rear window out, would be a good time to tint the rear window. Much much much easier! Also, when I get done tinting, I use an exacto/utility knife to remove about 3/8" of tinting from the edge so the butyl tape will have a clean surface to adhere to.

 

i had a local window shop replace my old rear window with a good used one i had obtained from one of the guys on this site. no butyl was used, only the epoxy glues.
be sure that u place spacers between the bottom of the glass & the channel so that u have sufficient space to re-install the stainless window surround trim on the clips.
check to be sure that your clips are all good before the installation of the glass.

 

If you look down the window, it has a slight curve to it, don't make a bubble of your car!!! The lettering should be readable from outside the car as mentioned earlier.

Make sure to test fit the glass in position first. Get it centered side to side and top to bottom. Use foam "blocks" to prevent it sitting right on the flange. Put masking tape right across the glass and onto the car in the center horizontally and vertically. Then cut between the glass and car with a razor blade and trim, now you have alignment marks for putting the glass in cuase once it hits the butyl tape, that is where it is going to stay.

Also, take a good look and see how far out you can run the butyl tape. If you put it right on the edge of the pinchweld it will be plainly visible from inside and possible the outside too, even with the chrome on. You want a good seal, but you also want it to look nice. Remember it will be visible from the inside so try to keep it straight as much as possible.

And as Gerry said, MAKE SURE you use spacers at the bottom. They are just chunks of rubber (any glass shop will have them) but the butyl tape stays soft and over time the window will actually slide downward just due to gravity.

Once you have the glass in place, you can smack with with your hand..open palm only, to help seat it..you can see the seal through the glass.

Once at that point, I install clips, then I usually use a tonque depresser to work the tape up the top side of the glass as well....or if you wish a better way now is with some urethane sealant to make sure water never gets in....I also fill the lower channel more than most people would, this is a water collecting area so if you fill it up nice more of the water runs out instead of sititng in there rusting out your car. Don't forget the trim needs to sit in there too, and the clips need to flex to attach the trim.

later
Tim

 

I would never use butyl to install a windshield or back glass. The glass when glued in becomes an important part of the structural integrity of the body, along with being much more durable and resistant to leaking.
Using butyl is a good way to start rust problems in the pinchweld.

 

Actually the old windows and backglass were installed with butyl tape...but today its much better to use urethane and get some strength in there as well.

later
Tim

 

I think GM was actually using glued in glass by 1970 and possibly a few years prior. It was no where near the quality of today's windshield urethanes though.

 

Well that is possible but it was used by the oems right up to the 80's. All the parts cars I ever had used butyl for all the installs, although some seemed dry, maybe that is the sealant you are talking about?

The cars were designed for butyl but there is no excuse for not useing urethane these days. Its superior in every way.

later
Tim

 

I wish people would stop perpetuating the myth that glass is a structural part of the car because it is NOT

Glass can not be put in tension or compression. Any load placed on glass will make it crack. All glass used has a metal frame or wood frame around it. Just like in a house, above all windows, you have a header beam made of two 2x4 or 2x6. If you have ever taken a mechanical engineering class in static loads and/or dynamics, you would have learnd that glass fact. Glass is there for cosmetic/viewing purposes only.

Reason for urethane is it makes a better seal for a longer time.

I agree with Tim, butyl ended in 79-80 time frame.

 

Actually George, I do beleive the reason that urethane became so popular was the strength it has...in an airbag equipped car the w/s must stay in or there is no support for the airbag and it becomes useless.

I think once a w/s is glued in with urethane, it does add some strength to the struture. Its no coincidence that you have larger and more sloped windshields today, something never possible with butyl as it would not help the larger opening strengthwise. Grab a piece of glass and try to pull it apart. All materials have some strength, and I remember readiing that the fourth gen camaro windshield in 93 was only possible due to advanced glass engineering.

Regardless, urethane is the way to go for sure.

later
Tim

 

Jason, urethane does not come in a tape. It comes in a tube and you run the bead onto the pinchweld first. It needs to be primed and the glass needs to be etched as well. Make sure you have your trim handy as you will want to set the height of the glass with the trim on so you don't end up with trim that doesn't fit.

You'll want to test fit the windshield first as well. Mark the center and sides with tape midway as it will help you and friend eyeball where it needs to go as you set it in once you put the urethane down.

Run a 3/8" bead, not too high on the bottom edge or it will end up in you view, set windshield in, put your trim on, make sure its ok (adjst as needed and use rubber blocks or shims of some sort to get the right height and then let setup for 24 hours. Once cured it won't move at all, and you can pull out your shims or blocks if used.

later
Tim

 

The difference in technology of windshield installation is the duties of the windshield since the mid 70's and the cars of today. The windshield is no longer just to see out of and keep the elements out but is part of the structural integrity of the cars of today and also is what backs up the passenger side air bag and supports the roof in a roll over. All windshield installs are governed by the Federal Motor Vehicle Safety Standards, specifically FMVSS 212 and FMVSS 216. The windshield is required to remain intact in a head-on collision and in event of a roll over. The glass and the pinchweld (body) must be prepared properly to insure proper adhesion. My advise to all is to consider very carefully who is installing your windshield. If not done correctly, your safety could be at risk, as well as your life and the life of your loved ones. There are still shops out there installing windshields in today's cars using yesterdays procedures. Most insurance companies require technicians to be NGA certified that are employed by shops that contract to install windshields on their clients cars.

For more info check with the National Glass Association at "www.glass.org" and the federal safety standards
at "www.nhtsa.dot.gov/cars/rules/import/FMVSS" .

FMVSS 205 - Glazing Materials - Passenger Cars, Multipurpose Passenger Vehicles, Trucks, Buses, Motorcycles, Slide-In Campers, and Pickup Covers [designed to carry persons while in motion] (Effective 1-1-68)
This standard specifies requirements for glazing materials for use in motor vehicles and motor vehicle equipment for the purpose of reducing injuries resulting from impact to glazing surfaces. The purpose of this standard is to ensure a necessary degree of transparency in motor vehicle windows for driver visibility, and to minimize the possibility of occupants being thrown through the vehicle windows in collisions.

FMVSS 212 - Windshield Mounting - Passenger Cars (Effective 1-1-70), Multipurpose Passenger Vehicles, Trucks, and Buses with a Gross Vehicle Weight Rating of 4,536 kg (10,000 lbs.) or less (Effective 9-1-78)
This standard requires that, when tested as described, each windshield mounting must be anchored in place and retain one of two specified percentages of its periphery in a crash situation. The purpose of this standard is to keep vehicle occupants within the confines of the passenger compartment during a crash.

FMVSS 216 - Roof Crush Resistance - Passenger Cars (except convertibles) (Effective 9-1-75) and Multipurpose Passenger Vehicles, Trucks and Buses with a Gross Vehicle Weight Rating of 2722 kg (6,000 lbs.) or less (Effective 9-1-94) This standard specifies requirements for roof crush resistance over the passenger compartment.

I hope this helps to alleviate some of the confusion as to what adhesives should be used and the purposes of the glass.

 

Good stuff, Rob! Not sure what a difference it would make in a 72 or earlier machine but it can only be better than butyl tape.

later
Tim

 

The difference it would make is that the windshield will not "sink" (get closer to the pinchweld) or "sag", (slide down the incline) over time as with butyl. Butyl never cures and is always in a "tar-like" state. In conditions of extreme heat it gets softer and will allow the windshield to sink and sag. And of course, urethane will add strength and rigidity to the area surrounding the windshield.

 

I was thinking more in the way of safety, but yeah butyl is a gooey mess constantly. Used to drive me nuts.

Later
Tim

 

A few months ago I removed my rear window to get some rust damage repaired. The rear window is original to the car. The lettering is readable from the inside, backwards from the outside. I reinstalled the rear window a few weeks ago. I reinstalled it so that it "Makes a bubble of the car" in other words it is installed "CONVEX and not CONCAVE". The rear window will not install with the words readable from the outside and it will not install with the curve to the inside. Whats the deal here?

 

Lettering was probably put on backwards? I don't know....when you say it won't install with the curve to the inside do you mean it pysically won't fit??

later
Tim