|© AP Photo/John Donegan
Sebastian Vettel's dominating practices at the Australian Grand Prix came to a halt on Saturday when his Red Bull had a hydraulic failure.
The three-time defending world champion set the fastest times in both practice sessions Friday, raising the possibility of continued dominance in 2013's opening race.
But he steered off the track and parked the car late in Saturday's session, with his team heard over the radio warning him not to shift gears as there was a hydraulic problem.
Vettel, who gives a name to his car each season, calmly removed the steering wheel from "Hungry Heidi" and made his way back to the garage.
Rain hit the Albert Park circuit 15 minutes into the third and last practice session.
Lotus' Romain Grosjean was fastest before rain arrived, ahead of Ferrari pair Fernando Alonso and Felipe Massa, although most drivers did not set meaningful times.
Grosjean's best was more than a second slower than Vettel's fastest time on Friday.
Cars emerged later on wet, then intermediate tyres, eager to test out their wet-weather settings as more rain was forecast for later in the day, raising the chances of a wet qualifying session.
The forecast for race day Sunday is for cool, cloudy but dry weather.
However, Melbourne is renowned for its fickle climate and rapid changes in conditions.
Friday's practice times had indicated that the Red Bulls would once again be the early season pacesetter, with Ferrari, Mercedes and Lotus providing their closest competition.
McLaren, which has a more innovative design that will take time to fully adjust to, was well off the pace and more likely to be fighting the likes of Force India and Sauber.