The Mechanic: windshields

November 22nd, 2011 -

Made of two panes of glass sandwiched together with a plastic liner fused between them – and their structure is remarkably stiff

windshield-chip-image

photo: shutterstock

No more cracks about windshields

By Dave Redinger

Is your windshield cracked? If it is, you are putting yourself and passengers in harm’s way because the glass supports the roof and is structurally part of the body (stiffening the windshield posts and cowl section).

Windshields are really sophisticated these days – made of two panes of glass sandwiched together with a plastic liner fused between them – and their structure is remarkably stiff.

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In the old days the glass was actually floating in a rubber gasket. The thought being that it wouldn’t break as the old, flexible bodies moved and shook. The down side of this type of construction was that passengers (not belted in back then) risked the possibility of being ejected into the crash as the glass popped out.

Newer stiffer frame designs, plus legislation against occupant ejection, lead to the development of the windshield’s being structurally part of the car. It’s actually glued into position.

The windshield in your car performs several tasks. In some vehicles the front glass directs air bag inflation to insure correct positioning when they are needed. When the bag deploys (in micro-seconds with a speed of 300 km/h) it’s directed up against the glass and angled back toward the occupant. Having a broken glass will compromise the energy transfer.

So, to be fully protected by your vehicle’s safety systems, replace the windshield if it is cracked. And get stone chips fixed before they turn into cracks.

Dave Redinger has more than 40 years’ experience as a mechanic and has run his shop, Doctor H Honda Specialists, in Toronto for the past 26 years. He’s also a radio talk show host and produces several television shows.

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