01282016BobBusIn my training courses, I typically explain that my instruction is not vehicle specific. With all the old and new vehicles in the marketplace, it would take months instead of days to teach automotive glass installation one vehicle at a time. Instead, I teach technicians how to trail blaze. Considering this is what he does every day, it makes all the sense in the world.

Today’s automotive glass technicians will see hundreds of different vehicles over the course of their careers. At the beginning, every vehicle is new. As they progress and become more experienced, some vehicles will become familiar, but every year new models are introduced, new challenges are posed and trailblazing is employed again and again. So, technicians are constantly figuring out a new method of installing almost daily and most certainly weekly.

I recently did some training at a bus facility in Washington state that illustrates this concept very well. The city buses used in this facility are the Gillig brand. They have a two-piece windshield made up of rather large bubble-type glass parts. They are gasket set with two inserts that lock the gasket to the glass surface and the pinchweld. I must admit that I have not done a great many of these types of buses so I was as new to this as my students. I needed to trail blaze.

At first sight, the installation seemed obvious. Remove the insert from the glass-locking portion of the gasket and push out the glass, lip the glass into the gasket, seal it up and move on to the next. The problem was the glass is deeply sunk into the gasket due to its size, so just pulling out the glass-locking insert wasn’t enough. We pulled out the pinchweld-locking insert and tried to push out the glass. It came out badly shattered, but it was out.

Now we had to install the new glass. Experience told me that we should lubricate the gasket and use a plastic stick to lip the windshield into the gasket. Wrong. We tried and tried to lip the glass in, but it wouldn’t go. The tension on the glass was too great and it would surely fracture if we forced it.

How was I going to get this glass into the opening? I turned to my experience from the late 1970s and used a technique I call three-siding. I lipped the glass into one side of the gasket and “roped in” the other three sides. However, I needed to adapt the method slightly to work on this bus. Instead of lipping in the bottom and roping in the top and sides, I had to lip in the squared off side and rope in the top, bottom and rounded side.

Here how it works:

  • I started by pushing the glass into the well-lubricated center dividing-gasket channel making sure that the top and bottom corners were around the glass edge.
  • Then I separated the gasket from the pinchweld on the other remaining sides and attached it to the glass edge.
  • Using a hook tool from the inside, I lipped the gasket down and around the pinchweld on the top, bottom and rounded side.
  • I spanked it into place to seat it firmly into the gasket.
  • I dried out the gasket and sealed it between the glass and the gasket and between the gasket and the pinchweld.

Once we adapted our windshield installation, we learned how to remove the glass differently.

Here’s what we learned:

  • For the second bus, we removed the top and bottom inserts, and pushed out the glass and gasket assembly from the inside separating it from the top, rounded side and bottom, leaving the center attached to the body.
  • We removed the gasket from the glass edge on the three sides and pulled the glass from the center dividing gasket.

The glass came out whole and undamaged and went in without a problem using the previous installation technique we developed on the first bus.

Morale of the story? Use your head instead of your muscle and learn to trail blaze. Your job will be a lot easier.