Red Bull Racing's Sebastian Vettel set the fastest time again in the second free practice session of the United States Grand Prix at Circuit of the Americas.
Fastest in this morning's session, Sebastian Vettel set the best time early in the second session but he was called back to his garage to have a water issue fixed.
His teammate Mark Webber and Ferrari's Felipe Massa traded fastest time for most of the session until Vettel emerged quickest of all.
Sauber's Kamui Kobayashi lost time when the team had to repair a broken exhaust.
Meanwhile, Vettel lost a great deal of time in the garage as the Red Bull mechanics worked on the water issue.
Heikki Kovalainen's Caterham had a slight contact Jean-Eric Vergne's Toro Rosso. That damaged the front wing of the Toro Rosso and cut a tire of the Caterham.
Vettel finally got back into action, and quickly set the fastest time with a 1m37.718.
In the last moments of the session, Pastor Maldonado's Renault engine failed.
In the end, Vettel's time remained unbeaten.
Webber classified second ahead of Fernando Alonso's Ferrari, Lewis Hamilton (McLaren), Jenson Button (McLaren), Felipe Massa (Ferrari), Nico Rosberg (Mercedes AMG), Bruno Senna (Williams), Kamui Kobayashi (Sauber) and Michael Schumacher (Mercedes AMG).
Fastest in this morning's session, Sebastian Vettel set the best time early in the second session but he was called back to his garage to have a water issue fixed.
His teammate Mark Webber and Ferrari's Felipe Massa traded fastest time for most of the session until Vettel emerged quickest of all.
Sauber's Kamui Kobayashi lost time when the team had to repair a broken exhaust.
Meanwhile, Vettel lost a great deal of time in the garage as the Red Bull mechanics worked on the water issue.
Heikki Kovalainen's Caterham had a slight contact Jean-Eric Vergne's Toro Rosso. That damaged the front wing of the Toro Rosso and cut a tire of the Caterham.
Vettel finally got back into action, and quickly set the fastest time with a 1m37.718.
In the last moments of the session, Pastor Maldonado's Renault engine failed.
In the end, Vettel's time remained unbeaten.
Webber classified second ahead of Fernando Alonso's Ferrari, Lewis Hamilton (McLaren), Jenson Button (McLaren), Felipe Massa (Ferrari), Nico Rosberg (Mercedes AMG), Bruno Senna (Williams), Kamui Kobayashi (Sauber) and Michael Schumacher (Mercedes AMG).