Replacing Your Vehicle’s Windshield? Here is Your Windshield Replacement Survival Guide.
A vehicles windshield provides the occupants a barrier from road debris and the outside elements. But most people don’t know a windshield is designed for structural safety in case of an accident, especially a rollover. A windshield is a vehicles third most important safety feature behind the seat belts, and air bags.
Windshields are like basketball backboards for air bags. So if you have a damaged windshield your air bag may not function correctly. It actually may inflate out the windshield cavity, rather than towards you. Or it won’t adsorb any pressure because your windshield simply pushes out.
Most consumers are not aware that when technicians replace your windshield, there is significant scratching to the “pinchweld” where the glass bonds to the car. These scratches must be prepped using paint and rust prevention steps. They should not simply leave exposed scratches where moisture from the exterior side can cause rust to develop.
Here are some questions you should ask your auto glass company:
- Is the new glass OEM?
- Did they remove the brand label on the windshield?
- Does the new glass have a shade band that matches your old glass?
- Is the new windshield the same color glass? (glass is actually colored, not clear)
- Does your windshield have a rain sensor?
- Is your windshield heated? (companies will install non-heated and charge for heated)
- Does the windshield have the right bracket for your rear view mirror?
- Does the new windshield have the same third visor as your old glass? (the painted black design which you can see around the rear view mirror on most cars)
- Are they using a universal trim molding, or the actual trim molding part for your vehicle?
- Does the company pay to fix paint scratches, if made by the auto glass technician?
Always inspect a piece of glass for scratches and distortion before it’s installed.
Types of Automotive Glass
A windshield is actually two layers of glass with a laminate material between the layers, what is called “laminated glass”. Laminated glass is extremely hard to puncture or break apart. That’s why a large object like a stunt man, can impact the windshield without breaking through. The strength of laminated glass combined with proper adhesion of the windshield to the body of the car provides massive strength against the roof collapsing in a rollover.
All of the other windows in your vehicle are “tempered glass”, which means they break into tiny fragments to reduce injury to the occupants. (a small fraction of vehicles have laminated side and rear windows also)
Today’s vehicles use urethane as the adhesive to bond the windshield to the vehicle, like a glue. Some urethane after complete hardening which can take 2-4 weeks, can hold 500 pounds per square inch of pressure. That’s one reason why you could never simply push your windshield out. Impossible! Some urethane allows you to drive away within one hour after installing the windshield, hardening just enough to withstand vehicle accidents. When your replacement has been completed, make sure to inspect the inside of your vehicle around the edge of the glass. Make sure no urethane has oozed out into view or onto your vehicles interior. This is more common then people realize and needs to be fixed immediately before the glue hardens! bongs
The urethane is normally heated, then applied to the glass or car body at the raised temperature. Depending on where you live or the application, they can use different kinds of urethane, even a cold temperature apply that is not heated. Temperature has a huge impact on the adhesion qualities of the windshield. I would recommend never getting your windshield replaced in temperatures lower than 55 degrees, or higher than 105 for the best results if possible. This is easy if you have the glass replaced inside of a shop or in a shaded area. Direct sunlight can heat the windshield to over 125 degrees!
Urethane does have an expiration date, so make sure you ask about this before a technician begins replacing your vehicle glass. Using expired urethane means minimal bonding power and the windshield has a chance of coming out during an impact. All urethane is made with an expiration date printed on the tubes, and if they don’t call someone else!
Paint Scratches, Rust, and Proper Windshield Installation
Deep vehicle scratches can turn into major problems later. Moisture will enter through a scratch and attack your vehicles body causing rust later. For people who live by the ocean, this can be disastrous for the structural integrity of your vehicle down the road near the windshield. If you are buying a used vehicle, make sure you check around the edge of the glass and under the trim molding for evidence of rust. Rust will spread under your paint, it is amazingly aggressive.
If the rust spreads to the “pinch weld” which is where the urethane is placed, the urethane will not bond and a windshield will leak or can even be pushed out. This can cause thousands of dollars in damage from water leaks or can even can cause death in an accident! If the rust moves into this area the technician must remove it before applying the urethane, or the vehicle must be sent to a body shop for repair.
Make sure the technician takes steps to prep and repair scratches to the pichweld. There is primer paints, metal rust prep chemicals, and other ways to cover scratches to reduce the appearance or spread of rust. The most important areas are where water will contact your vehicles body, especially under the exterior trim molding. That trim is not water sealed between the body and glass. The water seal comes from the urethane bead