01-17-2008, 08:05 AM
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Senior Member
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Join Date: May 2007
Location: Delaware
Posts: 171
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 Quote:
Originally Posted by Brad Baum
I happened to be the one that ran the nuts down on the studs in the cowl. I thought I stopped at what felt just firm. The next morning, Mr. Rosenburger fould the glass was cracked. What did I do wrong?
Brad Baum
Escondido,Ca
750b
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Assuming that the new glass had no flaws at all, the crack probably came from an unevenly applied stress. One guess would be that the side posts (chromed vertical elements that carry most of the load of the windshield) might have been tightened down too much before tightening the cowl studs. If so, the glass might have been stressed unevenly when pulling down on the studs. The reverse situation (tighten cowl studs completely first, then side posts last) might have the same effect. When I installed the windshield on my Spider, I had no problems with cracking (and none appeared in the past 8 years or so). But I'm pretty sure I installed ALL the nuts on the posts and studs before a final tightening. It might also help to start the final tightening of the nuts at the center cowl stud, then working out to the side posts while alternating sides. Like torquing down a cylinder head, you want to keep the stress uniform across the surface in order to avoid stress concentrations that result in warpage / damage. Just my two lira, your mileage may vary.
Jim
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62 Giulia Sprint
65 Giulia Spider Veloces (two)
88 Milano 3.0 L
91 Ducati 900 S/S
06 Ducati Paul Smart 1000
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