Auto glass installation is an involved process consisting of many different steps to ensure safety and quality workmanship. The AGC professionals have broken down the process of auto glass installation into seven different, smaller steps to help better understand the overall process.


The Seven Steps of Auto Glass Installation

1. Pre-Inspection

Pre-inspection is one of the most important steps in a successful installation. It can mean the difference between good and bad customer relations as well as a safe or unsafe installation. The experienced technician not only looks at the inspection as creating a level playing field, but also as an indication of how the installation is to proceed and if it can be done at all. Items to look for are:

  • Dents and scratches in the work area - Concentrate on the passenger side of the vehicle. The passenger side is the least noticed side of the vehicle, yet the most susceptible to damage.
  • Early signs of corrosion - If corrosion is visible before moldings are removed it is an indication that there is more corrosion present under the glass or molding. It may be necessary to discuss bodywork or the possibility of denying the installation according to the ANSI/AGRSS 002-2002 Standard.
  • Molding fit - If the molding is not fitting flush to the body or glass, it could indicate a previous installation or other hidden problems. This also should be discussed with the customer.
  • Missing or damaged parts - This also can indicate a previous installation. It could mean the installation may take longer to complete to the customer’s satisfaction.
  • Aftermarket paint jobs - These usually appear as “orange peel” texture, improper color matching, or overspray on moldings. This can indicate previous bodywork and may cause problems with glass fit or paint peeling by removal of the molding or protective tape.
  • Interior stains or damage - Check the seats, floor, headliner and interior garnish moldings for damage.
  • Electronic and mechanical items - These include: wipers, radio, lights, window regulators, power door locks, etc.

It is always a good idea to inspect the vehicle in the customer’s presence. But if this is impossible a Pre-Inspection Form will help in making the inspection more professional. Complete the form and leave it for the customers along with their copy of the work order.

2. Protection

Once the pre-existing damage is noted, the next step is to protect the vehicle from damage that the technician may cause. Habits to develop are:

  • Drop cloths for interior protection - It may be a good idea to use shower curtains as a drop cloth. It will not allow liquid to penetrate the vinyl and it can be used as a waterproof cover for the pinchweld opening in bad weather. Another inexpensive option is a fitted bed sheet. It can be draped over the back of the seats and protect the entire interior.
  • Fender covers for exterior painted surfaces - DO NOT place toolboxes on the vehicle, only individual tools being used. An inexpensive alternative to mechanic’s fender covers is an old towel.
  • Use protective tape on susceptible painted areas - These can include the fenders, top corners and along the hood. The best tape to use is a heavy fabric tape, such as duct tape. Stick the tape to your shirt or fabric to take away the aggressiveness of the adhesive. It is unnecessary to flatten the tape to the surface. Just drape it over the area to be protected. Then remove it as soon as the danger of damage is over. Make sure that you don’t use duct tape on aftermarket paint.
  • Tape up the defroster vents - The defroster vents are open to any debris that may fall from the pinchweld or the broken glass. If not covered or cleaned out, the customer could be injured from flying glass or dirt when the defroster is used.

Always admit damage to the customer if it occurs. Trying to hide damage you caused will only upset the customer more than admitting your mistake.

3. Removal

The removal step of the installation procedure has always been the most difficult part. However, the introduction of power tools and the new hand tools have greatly eased our job. The major thing to remember is that the goal is to get to the edge of the glass. 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, the following procedures are recommended.

  • Have the replacement moldings available. Whether you use them or not, replacement moldings should be available in case they are damaged. It also assures that if bent or misshaped, the job will always look good when finished.
  • Pull the cowl panel. In most cases the cowl should be pulled to allow for the best bottom bond. The passenger side airbag, in most cases, depends on the adhesion of the bottom seal of the windshield to position it properly. If the cowl is not pulled the bottom bond cannot be assured.
  • 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.
  • When using power tools, lubricate the tool by spraying water on the adhesive to be cut and on the blade. 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.


4. Preparation

Preparation includes the two surfaces to be bonded, the glass and the metal pinchweld. This is a very important step. Improperly preparing the surfaces can mean the failure of the bond, resulting in leaks, or even worse the glass part separating from the metal completely.


      • Use an adhesive system. Only use the preps, primers and cleaners recommended by the adhesive manufacturers. DO NOT mix brands.
      • Clean the glass with adhesive manufacturer-approved glass cleaner. Always clean the bonding edge first while the towel is at its cleanest and then continue to wash the transparent area last.
      • Use foaming glass cleaner to clean the glass. This pinpoints contamination by separating the foam. Once you locate the contamination wipe or scrub the area and retest the area again to assure the surface is clean and contaminant free. Remember to always ask your adhesive manufacturer for their recommendations for cleaning the glass.
      • Know the procedures for prepping the glass in all situations; fritless glass, encapsulation bonding, and PAAS bonding.
      • Use only adhesive manufacturer-approved applicators.
      • Allow all preps and primers to dry thoroughly.


      • Remove all surface corrosion and repair according to adhesive manufacturers’ recommendations. Urethane cannot adhere to rust. It must be removed and prepared correctly.
      • Clean all dust, dirt, oils and greases from the metal surface.
      • Prime only scratches or un-primed painted surfaces.
      • Leave 1-2mm (1/16”) of old urethane on the pinchweld. This improves bonding. Urethane adheres better to itself than to other surfaces.
      • Dry set the glass and the moldings. This procedure assures the best positioning of the glass and the flush fit of the moldings.

Another important preparation is to check the condition of the gravity stops and/or setting blocks. They may have to be replaced or added. Prepare both bonding surfaces and plan for any other procedural conditions.

5. Installation

Installation consists of the application of the urethane, the setting of the glass in the opening and the installation of the decorative moldings and cowl. To guarantee the best results of your installation you should follow these simple procedures.

  • Use a triangular adhesive bead. A triangular bead assures a smooth and solid bond to the glass. It “wets-out” solid with no bubbles or air spaces.
  • Make sure that the bead is tall enough to make contact with both the glass and the metal surfaces. This is especially important when the moldings are placed on the glass before setting it into the opening (blind set).
  • DO NOT use butyl tape as a dam. Butyl is not compatible with urethane adhesive. If a dam is desired, only use open-celled foam dams recommended for automotive use.
  • Replace acoustical dams. Most acoustical dams are located at the bottom of the pinchweld area. They are there to muffle the engine noises that filter up from the engine compartment.
  • Make sure that all molding clips are in good condition. Replace if necessary.
  • Make sure that the pinchweld is clean and dry before the adhesive is applied. Urethane cannot adhere to wet surfaces. This includes condensation due to cold weather.
  • Test every job with water after setting the glass. This will check for leaks and help in curing the adhesive.
  • The use of suction cups when setting the glass assures that the bonding surfaces are not contaminated by the oils present in the hands. If hands are the preferred method, care should be taken to eliminate the touching of the bonding surfaces. Always use disposable gloves when handling the glass.

6. Clean up

As far as the customer is concerned, cleanup is the most important step. They expect that the vehicle is left cleaner than it is found. One way to make this step easier is to be as neat as possible throughout the process of installation.

  • Use approved solvents. Most adhesive manufacturers produce a solvent specially designed to be used with their adhesives. It is adhesive-friendly and will not contaminate the bond. Release agents are NOT adhesive-friendly. They can break down the seal and cause failure in the bond.
  • Use damp solvent cloths. Soaked towels can cause too much solvent to penetrate the adhesive.
  • After vacuuming the vehicle, give the customer warnings. It is very possible that all the glass will not be cleaned up completely. Recommend that a professional detailer be contracted to fully clean the interior.
  • Clean all the glass. It is good customer service to clean all the glass on the car, not just the one replaced.
  • Don’t forget the hidden mess. The hidden mess is under the door latch, in the armrest, on the interior “A” pillar, the steering wheel, and behind the rearview mirror.

7. Post-Inspection

This step includes: tool inventory, extra parts, paperwork, and customer instructions

  • Give the customer instructions.
    • Drive-away times
    • Venting the vehicle
    • Car washes
    • Tape removal
    • Warranty information
  • Check for any left behind tools.
  • Make sure all parts are installed.
  • Make a critical inspection of your work. If possible have the customer make their inspection.
  • Make any notes on the work order of any unusual circumstances such as: rust, customer concerns, warranty adjustments, and body deformity.
  • Thank the customer for their business.