A smudge-free windshield is essential to safety on the road. Properly installed glass should sit flush with the frame, and the gaps should be uniform around the edge.
Technicians use a rope and soapy water to set the windshield. They also apply a primer to both the windshield and the frame of the car for a stronger bond.
Remove the Wiper Arms
A windshield is a vital part of your vehicle’s safety system, airbags, and seat belts. It helps to keep dirt, rain, and insects from flying into your face while you drive and provides you with the visibility you need to see clearly. The windshield is also a crucial element of your vehicle’s structural integrity, so keeping it in good condition is important. A bad windshield can cause serious damage if you’re involved in an accident, so be sure to hire an experienced mobile mechanic who understands the intricacies of auto glass repair and installation.
When you are ready to install your new windshield, you need to remove the old wiper arms first. Start by removing the cap that sits over the nut found in the wiper arm’s linkage joint. This can be removed with a wrench or a screwdriver, but it is important to use caution to avoid chipping the chrome or paint of your vehicle.
Remove the nut once the cap is removed, and pull off the wiper arm. You can now remove the old wiper blade and replace it with a new one if needed. Some wiper arms have a clip that holds the base of the arm in place. To remove this type of wiper arm, you will need to locate the pinholes on each side of the clip and insert a nail or a pin through them. Once the pins are inserted, you can remove the clip and slide the wiper arm off of the wiper arm post.
Before installing the new wiper arm, be sure to lubricate it with a silicone-based lubricant. This will make it easier for you to slide the wiper arm onto the windshield later. Be sure to apply the lubricant around the entire perimeter of the windshield gasket as well. You can use a simple rounded rod (such as a small Phillips screwdriver or tire tool) to work the lubricant into the seam between the windshield and the car body.
Remove the Molding
This is a step that technicians often skip because it’s messy and requires brute force to get your windshield out of the frame. This step is likely to cause the car owner a lot of grief, especially when the technician tries to pull your windshield in and it cracks or chips. The good news is that it can be avoided by taking your time and doing this correctly.
Start by using a tool designed to remove windshield moldings shaped like a Y with a hook on each end. This can be purchased from auto glass shops or most hardware stores. Start by hooking the Y end over an edge of the molding, then pull gently while exerting pressure. This will pop the edge loose, making it easier to remove. If this doesn’t work, you can try running a long piece of the fishing line under the molding, looping it around to the other side, and then pulling and
twisting to loosen the molding. You can also use a hair dryer or heat lamp and aim the heat at the molding until it heats up, then grab it with pliers and twist it off.
If you’re working on a brand-new vehicle with no damage, you may be able to skip this step entirely and simply use your pliers or hands to remove the moldings. If you’re working on a used vehicle that has been damaged or even just painted over, this will be necessary before the windshield can be installed.
Once the moldings are removed, your windshield can be glued back in place. Don’t forget to reconnect the wiper arms and test them out so they work properly again.
Clean the Glass
A car’s windshield gets dirty with road grime, bug guts, and weather. A dirty windshield can decrease visibility and make driving dangerous.
When a windshield is new, it’s clean, but that cleanness can diminish over time. The first step to a flawlessly clean windshield is to remove the wiper arms, molding, and any other trim pieces that hold the glass in place.
The next step is to scrub the windshield with a rag and soapy water. Cleaning the entire windshield, including the sides and edges, is important. This will eliminate dirt that may flow over the windshield in rain or during a car wash.
Many glass installers sell windshield cleaning kits. A kit includes a foam pad that attaches to a buffer or drill and cleaning compound. Using the buffer in a circular motion, buff the windshield to remove any film or build-up. After the windshield is buffed it’s important to wipe the windshield clean with a microfiber towel.
If a glass installer is being used, check the quality of the glass before buying it. Cheaper windshields often have optical distortion that can distract the driver. Some of these problems are not noticeable, but others can be identified by a simple test, such as holding a piece of graph paper perpendicular to the windshield and looking for any significant “ripple.”
Next, spray half the windshield with glass cleaner. Use a few squirts to fully cover the windshield. Start at the base of the windshield and move the clay in a straight, vertical line to the roof of the vehicle. Once the clay is on the roof, move it to a position slightly closer to you. Continue this process until the windshield is completely cleaned.
Apply Primer to the Frit Band
If your windshield was replaced in the last few years, chances are that a black urethane line runs around the perimeter of the glass. This is called the frit band and is used to seal and reinforce the adhesive bond between the new windshield and the frame of your car. It also helps with the overall durability of the windshield. This is one of the most important pre-installation steps and, unfortunately, is often skipped by technicians. If not done properly, it can lead to air leaks, water leaks, and corrosion under the urethane.
In order to get the most out of this step you will need to apply a glass primer. The primer should be applied according to the manufacturer’s instructions and then allowed to dry thoroughly. This should be done on both the old urethane and the new glass. Once the glass has been primed it’s a good idea to do a lap shear test to make sure the adhesive is bonding well.
To do a lap shear test you will need two pieces of glass about six to eight inches long and about two feet wide. One of the pieces should be primed and the other unprimed. Cut a cross-section about an inch thick through both bead areas and then use a plastic abrasive such as a Scotch-Brite pad to remove any contaminants stuck to the glass surface. Then repeat this process until the abrasive can no longer remove the contamination.
Most windshields are made of laminated glass. This means that two sheets of glass are glued together with a layer of plastic in between. This makes them much more durable than ordinary glass. This extra layer of protection can help keep debris from flying out your window while driving and makes it much safer if an object hits the windshield.
The last step of preparing a windshield for installation is applying urethane to the pinch weld. Urethane is similar to glue, and it holds the glass in place. It is important to apply the urethane evenly and quickly to ensure that it does not begin to dry or set before the windshield can be put into place.
Using the right type of urethane is also critical to ensure that the bonding surfaces are clean. Many auto glass shops use grease or petroleum-based products to help remove the windshield, but these types of lubricants can hinder the adhesive bonding process. In addition, if the urethane is applied too close to the edge of the glass it can cause a problem known as “sag.” Sag causes the adhesive material to slump over the edge of the windshield and can damage interior or decorative surfaces.
Another common mistake that auto glass technicians make is not cleaning the pinch weld well enough. This area is designed to hold the windshield in place, and it can be difficult to clean without damaging the windshield itself or the pinch weld. This is why it is best to use a tool called the soapy string, which is essentially a length of string that has been drenched in a soap solution.
Finally, following the recommended drive times given by your technician is important. This will allow the urethane to cure properly and allow for safe driving. Going out before the urethane has fully cured can cause the airbags to deploy prematurely and even result in the Windshield coming loose. This could lead to injuries or even death to vehicle occupants.