The Red Bull driver lost it going into the right-hander at Abbey after something appeared to snap on the front of his car and the nose cone dropped with the GermanÃ¢â‚¬â„¢s front wing scraping along the track.
But Vettel managed to crawl back to the pits with the Red Bull mechanics now carrying out an investigation into the failure.
If the failure is on the chassis side, Vettel is in big trouble as the problem cannot simply be fixed by attaching a new nose cone, which will be the inevitable step.
The Red Bulls were the only cars to go sub one minute thirty with a time of 1:30:958 Ã¢â‚¬â€œ the quickest lap of the new ‘Arena’ circuit, just a three hundredths of a second quicker than Webber.
FerrariÃ¢â‚¬â„¢s Fernando Alonso and MercedesÃ¢â‚¬â„¢ Nico Rosberg were less than a tenth slower to take third and fourth.
The top 10 were separated by just six tenths of a second in a close session as the teams prepare for this afternoonÃ¢â‚¬â„¢s qualifying session.
McLaren, who last night ditched the significant upgrades they had brought to Silverstone, could only manage seventh quickest with Lewis Hamilton setting a 1:31:549 just five thousandths of a second quicker than Michael Schumacher.
HamiltonÃ¢â‚¬â„¢s team mate Jenson ButtonÃ¢â‚¬â„¢s disappointing weekend continued as the world champion could only set the twelfth-quickest lap.
Renault had a strong final session as Robert Kubica was sixth fastest just behind FerrariÃ¢â‚¬â„¢s Felipe Massa, while Vitaly Petrov was just a tenth outside the top 10 and WilliamsÃ¢â‚¬â„¢ Rubens Barrichello.
The big surprise of the final session was SauberÃ¢â‚¬â„¢s Pedro de la Rosa finding some pace to set the ninth-quickest time, four tenths quicker than SauberÃ¢â‚¬â„¢s hero in Valencia Kamui Kobayashi, who could only manage fourteenth.
Force IndiaÃ¢â‚¬â„¢s Adrian Sutil had a difficult session as a gearbox problem hampered his running as he finished fifteenth quickest, but the team have said on Twitter it is an easy problem to fix, and the German, who has scored points in six of his last seven races, should be back up to speed for qualifying.
At the back, Lotus were again the quickest of the new teams as Heikki Kovalainen finished nineteenth, albeit 1.6 seconds slower than Force IndiaÃ¢â‚¬â„¢s Vitantonio Liuzzi, but over a second quicker than Virgin RacingÃ¢â‚¬â„¢s Lucas di Grassi in twentieth.
While the top 10 are covered by just sixth tenths, Sakon Yamamoto in the Hispania was six seconds slower then Vettel in his debut race weekend as he stands in for Bruno Senna.
YamamotoÃ¢â‚¬â„¢s inexperience behind the wheel of an F1 car shows, because despite the car being poor by F1 standards, Senna is not usually that slow. Sadly, money talks, and YamamotoÃ¢â‚¬â„¢s inclusion at Silverstone is almost certainly a thanks from the team for his sponsorship money funding a new, much-needed chassis.
If we had the 107% rule in place for 2010, Yamamoto would almost certainly be slower, and would only be able to race on appeal to the stewards.
Whether drafting a rookie test driver in on the eve of a race is grounds for exemption remains to be seen, but it would not be a surprise if we see just that next year when the rule returns.
With hours left to go until qualifying the big questions surround Red BullÃ¢â‚¬â„¢s reliability. So far this weekend they have suffered electrical problems on WebberÃ¢â‚¬â„¢s car, brake pedal issues with VettelÃ¢â‚¬â„¢s car and now an apparent mechanical failure on VettelÃ¢â‚¬â„¢s car in the final session.
At Valencia, everyone praised the design and strength of the Red Bull as Webber survived a huge airborne collision with Kovalainen, this weekend, they do not appear to be so lucky.
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