Windshield Replacment

[SAE09]

Hi all, first post.

 

I have a 1999 GMC Sierra K2500, 5.7L I purchased new at the end of 98. The windshield was just replaced yesterday. There was a thin foam strip that runs along the top of the windshield opening, which sits between the edge of the glass and the body. It is no longer there.

 

What purpose does this foam strip serve? Is it simply a filler to keep debris out and deter ice from building up behind the glass edge? Should this be replaced? I am concerned that with the gap that is there now it can become a catch all for dirt, leaves, whatever, and could allow significant ice build up to occur.

 

Should this be replaced and is there a replacement part for this. Thanks

 

Rick

[Wingnut]

Should have came with your new windshield and they should have installed it.

[PGDriver]

Its called a foam dam strip and its purpose is to keep the urethane that is

put on the pinchweld from squeezing out if the bead isn't run perfectly and being visible in that gap at the top.

When we install glass we don't use it either as it collects sand and grit and rubs

against the body and will remove paint in worst cases. Dodge trucks have gone

away from using it even at the factory.

Its also used by poor installers to cover up damage they have done to your

pinchweld during the old windshield removal.

[SAE09]

Its called a foam dam strip and its purpose is to keep the urethane that is

put on the pinchweld from squeezing out if the bead isn't run perfectly and being visible in that gap at the top.

When we install glass we don't use it either as it collects sand and grit and rubs

against the body and will remove paint in worst cases. Dodge trucks have gone

away from using it even at the factory.

Its also used by poor installers to cover up damage they have done to your

pinchweld during the old windshield removal.

 

 

Ok, I wondered what purpose it served as the glass company did not replace it. I can see foam being a dirt and grit magnet.

 

 

What are your thoughts as to the gap that is left there since the foam dam strip is no longer there? What kind of solutions are there to fill that gap up?

I picture ice/snow building up in the winter and the freeze effect of that getting under the glass and heaving it up.

 

Here is a crude exaggerated cross section representing the gap left by the lack of foam.

 

Thank you for your help, I greatly appreciate it.

[PGDriver]

Personally I don't mind it and I see a lot of vehicles come into the shop,

some have a little dirt in the gap but before we start we just hose it out.

Next windshield if the gap bothers you ask the glass shop to show you

a piece of universal molding that can be attached to the top of the windshield

(I would use a 17mm piece) and see what you think. One thing ask them

to run a bead of urethane along the molding to make sure it doesn't come off the glass.

[SAE09]

Good thoughts, and I like the universal molding to finish it off for the next go around. I was thinking about the additional

bead of urethane. The gap between the glass and body is 4.5 - 5.5 mm depending where along the top its measured.

 

The other thing I forgot to mention as you may know, the glass has a black molding that runs around the entire edge

of the glass encasing the edge if you will, same as the factory piece that was in there.

 

Lastly, the top center of the glass, roughly 12 inches across or so, sticks up above the edge of the roof about 4 - 5 mm. So if you're looking

from the back of the roof toward the front, down the roofs angle to the glass, it sits proud of the roof by that much. I didn't show that in my rendering.

 

Thanks again for your advise. Have a great holiday weekend!

[PGDriver]

The black area around the edge of the glass is called the "frit" this is to stop the UV rays from

hitting the urethane and doing damage. As for the center of the window sitting up that sometimes

happens with some makes of windshields. They are made in the US, China and Mexico, some factories

will make a certain number for say GM, then remove the GM logo and produce aftermarket ones.

Sometimes these factories don't quite get them perfect. At our shop once the urethane bead is cut next

to the windshield we dry fit the new one on the old bead just to see how it fits before we cut away the

old urethane bead.

 

Hope this helps, nothing I would worry about... just a little sloppy.

[SAE09]

Thanks for the "new term" glossary for both of those parts (foam dam strip, and frit), but even more so for the background on the mfg process and end product shape.

Sloppy I agree. I am going to ask them to apply a small bead of urethane across the top down into the gap to alleviate the settling of water/ice/debris.

 

Another question. Is it common practice to remove the "frit" and apply urethane underneath that to help adhere that to the glass or even to try and push urthane under the edges of it? Reason I ask is it appears that there are remnants of urethane strings and wiped edges around the perimeter of the frit.

[PGDriver]

I won't run a bead of urethane in the gap if I were you because the next time they go to cut the urethane bead to remove the window it will not be pretty.

The frit is paint that has been applied to the windshield and baked on in the laminating process and can't be removed, what you might be seeing is the vinyl

that is laminated between the two pieces of glass (if it is clear) if it is black its a messy urethane job.