Vettel suffers car problems in Melbourne F1 practice

Frenchman Romain Grosjean topped the session with a best lap time of one minute 26.929 seconds in his Lotus on dry tyres before rain swept in with three-quarters of the session left.

All 22 cars swapped over to full wet weather tyres and Grosjean's time stood as the best in the inconclusive final practice before qualifying later Saturday ahead of Sunday's season-opening GP at Melbourne's Albert Park street circuit.

Vettel failed to finish the session when he pulled off the circuit on his ninth lap and was told on team radio that his Red Bull had hydraulic issues and not to shift gears.

The German three-time world champion clocked a best lap time of 1:29.808 well down on his times registered in Friday's practice.

The Ferraris of Fernando Alonso and Felipe Massa were second and third quickest behind Grosjean before the rain hit.

Alonso clocked 1:27.000 and Brazilian teammate Massa 1:27.241 in the session.

There was still no joy for the troubled McLarens with last year's Melbourne race winner Jenson Button trailing in 17th and teammate Sergio Perez 18th.

The wet weather prevented Lewis Hamilton from clocking an early fast lap in his Mercedes and he posted the slowest time of 1:47.246.

Rain was forecast to continue in qualifying amid tumbling temperatures and strengthening winds.