Bojrn is right! Install it yourself so it does'nt leak. As a collective group, glassmen are a sorry lot. Sorry to offend the 1% who installs correctly, but I have to call it like it is. (Oh, by the way, the w/s doesn't already come with a seal. If the w/s already had a kit on it, it was put on just before the glassman left the shop. I don't know why the hell some guys install the kit at the shop, but some of them do. Then again, I don't know why professionals cannot install a w-688 without assistance, but many of them need help setting the w/s into place.)
Rohrt: It depends on the age of your bodyman, whether or not is information is "current." A younger guy may fail to consider that f/g's do not have ingergral glass, whereby the glass acts as part of the structural integrity of the car.
Starting in 1982 ALL GM CARS have used the windsheild as part of the cars' frame. This the reason why it's important to install windsheilds with URETHANE ONLY AND NO BUTAL. Bozo glassmen couldn't fathom the concept of glass being part of the car's frame, and it took until the late 90's for them to catch on that butal-set w/s were a death trap wating to happen.
Starting in 1986 & 1/2, all vechiles used srtuctural glass, and it was a good decision on the manafacture's behalf. For instance, the 86 % 1/2 (aka 87) full size Ford truck maintained the same chassis/block as its 86 predessor. The intergrated glass, however, allowed an 18 pound reduction in the weight of the body. Best of all, the additional rollover strenght was an exponential amount. I don't recall the number, but it may have been 200 to 300% increase in chassis strentht.
The point of the diatrbe is that f/g bodies have flex. Therefore, urethane isn't the best choice for w/s, b/g installation. Urethane is fairly rigid, and the long term results is that it can break away from the body. Also, regardless to time frame, it can also cause the w/s to stress crack because body flex can be transmitted to the glass.
Butal, a pliable substance allows the body to exibit its natural flex. Simply, it's the best choice of installation of w/s and b/g in f/g cars.
The reason why it's getting hard to find butal is that--starting way back in 1982--federal law has prohibited ANY BUTAL useage in urethane installed glass.
I was a poineer and advocate in no butal in urethane glass installation, and it makes me ugly to think about one installing butal when it should be installed in urethane. The thing is that I was around during the conversion, and you repair as the manafacture intended. (If you want to get real technical, f/g's weren't installed in butal from the factory. I forget what the stuff was called, but it was a hard type of pukey. Even so, it has much more flex than that of urethane. Also, the more fussy people *****ed about replacments because it wasn't exactly like factory.)
A little about butal. NAGS (National Auto Glass Association) recomended 5/16 th's butal kit. That speck has stood since the first day of f/g's. The reason for the 5/16 th kit was that when the speck was set, w/s's were much thicker. If you look at an origional w/s, and compare it to a replacement w/s, you'll notice quite a differece in the thickness.
It was before I got into the automative industry (1979) when manafactures reduced the thickness of earlier w/s. I don't keep track of everyghing so I don't know if the problem has been compensated for, but one problem with the downsise was in rubber gasket w/s. The problem was that the replacemtn w/s flopped around in the gasket. To compund problems, replacment rubber gasket were made for the thicker glass. But they didn't make the thicker glass--duh!
Anyway, because it's not one of those thick, origional glasses, the 5/16th's kit will cause the w/s to sit a little low. As a result, the chrome will stand a little high. The 3/8th's kit will make the chrome sit tighter to the glass. Sometimes, the chrome will be a little tight. If you have problems snapping a clip, DON"T HAMMER IT WITH YOUR HAND! Rather use firm steady pressure to clip it. If that doesn't work, use a narrow, stout strip of wood as a cushion. Lay it on the chrome, and strike the wood with gentle, but sharp tap from a hammer.
(Back glasses are more receptive to a 5/16 kit. However, I also use a 3/8.)
More on butal: Use 3M brand, and get the round, not square, kit. 2 brands you want to leave on the shelf are CRL (C. R. Laurence) and PTI. Both butals string exessivly when removed. (Ever had the stuff string when removing it? You can rest assured that it's probally one of those brands.) In addition to the major mess, CRL has poor consistancy, and it will loose its height. In other words, it will eventually squish, allowing the w/s to sink in the pinchweld.
About windsheilds: Some of the board's most knowledgble guys can probally help you better sort this out, but f/g cars used 2 makes of glass. They are LOF and PPG. Ima' firm beliver that GM uses whatever it has laying around the factory as "factory correct," but the difference could be what plant the car came from. My 9 has PPG glass, and I replaced my orgional windshild with a PPG brand.
Stay away from Safelite (LSI) Gurdain, Pinkeltonm, and other bastard glasses. In addition to being incorrect manafactures, these glasses are known to be ill fitting replacments.
One brand that is a quality w/s isn't a correct logo, and it's made by the 4-letter-word-company. Carlite makes an expetional w/s, and the fit is exact. I hate to say it, but it's probally a better quality w/s than that of LOF and PPG: The tint--the overall coloring in the glass--seems to provide better day/night glare reduction.
I bought my PPG a shaded version to replace a tinted w/s in 1985, and the shade is quite skimpy. In fact, it's pretty much a joke as far as the defintion of a shaded w/s. (They may have improved through the years.) The Carlite shade, however, is a generous band, and it's quite dark.
One more thing, and I'm out of here. It's dealer's choice whether or not the kit is placed on the body or the glass. It has been my experaince that you get a better seal, and a better looking installation, if the kit is put on the body.
When you put it on the body, it makes postive contact with the body. Water runs downhill, so against the body is the more critical seal area. Not that you want any voids, but it's possible to have an air gap between the glass and the seal, and still not have a water leak. (It 'dont work that way if you have an air gap between the body and the seal.)
Also you get a better looking installation when the kit is placed on the body. When you install the kit on the glass, you may end up with a notiable gap behind the top/side garnish mouldings. When you place it on the body, you can maintain an exact position. For an ultra clean looking instlation, have the top/side garnish mouldings in place. Run the kit with just a nano-hair gap from the garnish mouldings.
Oh yeah, it's good advice to practice a couple of dry sets: One tip to help the ease of the installation would be to place the top of the w/s first. Because of difference between the top and bottom curves of the w/s, it's eaiser to judge the postion as you come down with the glass. (Make sure that you are above the stops.)
When you set the top first, the flatter area allows you fairly accurate positioning when the glass bites the butal. When you place the bottom first, sharper curve makes it so the glass has already bit the butal, but you have no way to guage the postion of the glass.
