by Bob Beranek
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Do you know what a seatbelt pretentioner is? If so, give yourself a prize. Since I have been training professionally and speaking on the safety system addressed in Federal Motor Vehicle Standard 208, I regularly ask my students this question.  Most people don’t know what it is, or what it’s designed to do.

Many people confuse the pretentioner with the fast-braking belt-locking system. The fast-braking lock is a mechanical device that restricts the slack of the belt in case of a fast stop or brake application. It can be placed at various places within the seatbelt system. It works almost like a pendulum when the brakes are applied aggressively. As the pendulum is forced forward due to the fast stop, it locks into the seatbelt mechanism and restricts the belt from releasing any more slack.

The pretentioner is different, however. The seatbelt pretentioner is a pyrotechnic device that works with the fast braking lock system. The mechanical locking device restricts any more slack, and the pretentioner takes up the slack that is there and pulls the occupant back into the seat. The pretentioner works on the same circuit as the other airbags in the vehicle so that all systems work together.

Some of you may have heard of victims of serious collisions having a burn mark where their seatbelts crossed their torso. That is the pretentioner doing its job of pulling the occupant back toward the seat. You may have a mark for a while, but it can save your life.

When a door glass, vent glass or any tempered part in a vehicle breaks, the glass can go anywhere. If some of the glass chips get into the housing that surrounds the pretentioner, then removal must be done with caution. You should not dig down into the pretentioner housing to retrieve any broken glass.  Tools digging down in the housing could cause damage to the electrical system that triggers the pretentioner.

To clean out the housing:

  • Use a vacuum cleaner to suck out broken glass pieces;
  • Use compressed air to blow out the debris;
  • Manipulate the belt to force out glass chips; and
  • Disassemble the housing and clean out the pieces of glass trapped within. The housing is quite simple to remove, and the results will be cleaner with less chance of malfunction.

My advice is not to ignore the seatbelt area when cleaning up a tempered glass break. It can cause a malfunction of the system and possible injury to the vehicle owner or passenger. Just be careful when working in or around the pyrotechnic pretentioner—the cost and time needed to replace it will most definitely eat into your profits on the job.

Bob Beranek is the president of Automotive Glass Consultants Inc. 

Complaints about glass quality are increasing right now, but I am a “pie in the sky” optimist. I believe that the Aftermarket Replacement Glass (ARG) will get better in the future unlike the current trend. The ARG market must up its game or go out of business and here’s why.

We all know that quality standards in the ARG market have been declining. It started with protruding PVB at the windshield edges so drastic that moldings couldn’t be attached without trimming it back. It progressed further with moldings applied so sloppily that we had to remove them and reapply our own, costing us more than we expected. Lately, we have mirror pads falling off, glass out of bend and parts failing to pass recalibration.  We lose money every time we have to then replace the cheaper glass we originally installed with an OE part anyway.

Like any business, ARG manufacturers may feel the need to reduce costs to remain competitive. Some of the ways a glass company can reduce cost is to reduce the quality control inspections, use less expensive add-ons like mirror and molding adhesives, and/or reduce labor hours where possible.  Waste is reduced by letting less-than first quality parts leave the plant and go on sale, rather than washing them out as defective. Fewer “defective” parts means less waste and more profits.

However, with the advent of Advanced Driver Assist Systems, the quality of ARG parts must be upgraded or their very existence may be in danger. The difference between the original equipment “dealer” parts (OE) and the ARG glass parts is the way the manufacturers get their specifications for production. The OE receives the specifications directly from the carmakers’ designers and engineers. The ARG gets their specifications through “reverse engineering.” The carmakers determine the tolerances they will accept with OE parts. ARG manufacturers determine their own tolerances, usually based on what the market will bear.

The OE has very tight tolerances because of the technology built into today’s vehicles. Some are performance driven while others are safety driven. Both performance and safety driven technologies are important to the carmakers because they want to make their vehicles attractive to buyers and their systems to work properly. OE glass parts specifications are important to the performance of the new technology.

ARG manufacturers cater to the vehicle owners. Some of those vehicle owners put the price of glass repair at a higher priority than the performance of the technology. In some cases, that is acceptable because a performance feature is the choice of the owner and, if the owner decides to bypass performance for price, that is his/her prerogative. An example of this might be the acoustical glass. ARG companies may not offer acoustical glass as an option because it is a patented process, and they choose not to purchase that technology from the patent owner.

However, safety technology cannot be bypassed for price. It must be made operable or the United States Highway Safety Act of 1966 is broken. If a safety technology is not returned to the glass part, then they will lose sales and possibly their whole business.

What does all this mean? I think it means that unless an ARG manufacturer wants to lose business to the dealers and OE suppliers, it will have to improve its quality, sell out or go out of business. I’m optimistic that the ARG industry will not disappear. They will make the adjustments to survive and will choose to improve their quality. Call me an optimist.