Fixing That Windshield
If damage isn't too bad, look at repairing it.
ED THOMAS
CONTRIBUTING EDITOR
Is there anything more aggravating than a dinged windshield? Sure, lots of things. But as replacements go, it's a simple thing that can take many hours if you don't do it very often. That's a good argument to let an "expert" handle it. But first, consider repairing the glass rather than replacing it.
Methodology to fix windshields has been around for more than 20 years, according to the Technology & Maintenance Council of ATA's Recommended Practice 429, Windshield Replacement & Repair. Because it's quicker and cheaper than replacement, glass repair is recognized and even encouraged by major insurance companies.
Procedures usually involve extracting air and contaminants from the damaged area and filling it with a polymer resin, the RP says. When cured, the resin behaves like glass, which means it seals the damage, allows clear sight through it and resists subsequent stone hits as well as the glass around it.
Glass industry associations have standards for fixing windshields and good technicians will follow them. Standards include using approved tools, materials and methods. If you've seen it done, you know that the process includes cleaning the ding or crack, then probing or drilling it as a dentist does with a decayed tooth. Drilling can relieve stress to keep a crack from spreading. Then the resin is spread or injected to fill the void.
Drying is fast, and usually the truck can go back on the road after just a little while.
It's possible to damage a windshield further while working on it, so the truck owner should have a replacement windshield on hand so he can revert to "Plan A." This is pulling out the damaged glass and installing the replacement — either a new or good used windshield. You've probably seen this done and maybe you've done it yourself, so you know it's a sometimes tricky and time-consuming project.
One of the disadvantages of replacing a windshield is breaking the bond or gasket between the glass and the cab's steel or aluminum. The new seal may never be quite as water- and air-tight as the original. Each truck builder has a procedure for installation of the original windshield, and this should be followed as closely as possible during replacement, says RP 429. The manufacturer's dealer is most likely to follow that procedure, but professional glass installers may also do it, or have techniques that can work as well.
If the seal is aged or cracked, it may have to be replaced, which is another project. The replacement seal and glass must both be exactly the right size and design, or the job becomes frustrating. If you call in a mobile repairman, don't be surprised if he has to take that glass back to his shop to trim it, or fight with the rubber gasket to get it seated in the channel (and meanwhile your truck sits). If it's OE glass or an OE seal and he's doing things right, he shouldn't have to struggle.
The flatter the glass and the simpler its shape, the less it should cost to buy. You should also get a price break if your truck has a two-piece windshield instead of a larger and more complex one-piece unit. However, prices can also depend on the number of parts floating through the aftermarket, and on the truck builder's pricing policies. Of course, the glass should meet DOT standards for optical qualities and resistance to shattering. Shop around, keeping in mind that a good, accurately cut windshield is better than a bargain-priced piece of glass.
When must you repair or replace a windshield? When the driver has trouble seeing through it, or an officer says so, whichever comes first. Dullness, discoloration and "sand-blasting" damage are also good reasons for a windshield facelift. Curiously, the Commercial Vehicle Safety Alliance does not include windshield damage as part of its out-of-service criteria, but an inspecting officer can cite state law or common sense to order that the windshield be fixed. Then, get to it.
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