Removing the old glass has always been the most difficult part of the installation process because of the physical labor required. However, the introduction of new hand tools, particularly power tools, has greatly eased this part of the installation. Remember, the goal is to get to the edge of the glass for easy cut-out. Once that is accomplished the rest is easy. To assure that the finished installation is both pleasing to the eye and safely bonded to the metal, here are some recommendations.
—Have replacement mouldings available, whether you think you will use them or not. It ensures that if even if the original mouldings were bent or misshaped, the job will always look good when finished. A good selection of universal mouldings comes in very handy to replace stretched or damaged mouldings.
—Have replacement clips as well. Even though clips are not used as often as they once were, some clips are unique. To make matter worse, many distributors do not stock a wide variety of clips because they don’t sell well and inventory turnover is low. I suggest determining the dominant car dealer in your market and obtaining the clips and retainers necessary to do those brands of vehicles. That way you will have replacements most of the time.
—Never disconnect the electrical components from the rear view mirror while the ignition is on. This could damage the vehicles’ computer or, at the very least, erase the pre-programmed memory. Either:
—Disconnect the wiring harnesses and remove the mirror and place it the back seat; or
—Remove the mirror from its pad and leave it hanging from its wiring harness.
—Pull the cowl panel. In most cases the cowl should be pulled to allow for the best bottom seal. The passenger-side airbag, in most cases, depends on the adhesion of the bottom seal of the windshield to position it properly. It also supports and solidifies the firewall. If the cowl is not pulled, the bottom seal cannot be assured and failure is a distinct possibility.
—When using hand tools for removal, start with the shortest blade in the cold knife and work up to the longer blade. This gives the technician more control of the tool and makes the cut out easier. Look for blades that have extra thinness, serration and coatings to protect the paint.
Use your body weight rather than your upper body strength to pull the cold knife. This allows you work more comfortably and reduces the chance of muscle strains or pulls.
—If you have a part with a rigid or metal-coated moulding system, use a plastic stick vertically to the pinchweld to break the moulding from the glass surface. Then force your cold knife blade between the glass edge and the broken moulding flap and under the edge of the glass. Then pull the cold knife normally. This method cuts out the glass and leaves the moulding in place which eliminates the need to pull the rigid moulding out to access the glass edge. The moulding also protects the pinchweld wall from damage from your tool.
—When using power tools, lubricate the tool by spraying water on the adhesive to be cut and on the blade itself. This reduces the harmful fumes caused by the high speed of the blades and also makes the tool work smoothly. Plain water is recommended over soapy water because it will not contaminate the bonding surface. All cut-out blades are flat on one side and beveled on the other. The flat side of the blade should be to the glass surface. The blade and the glass create a scissor-type action that eases the cut-out. The closer the cutting edge is to the power source the more torque and cutting power it has. So, use the shortest blade possible to cut the material and protect the interior trim.