Red Bull's brake supplier Brembo has ruled out failure of its braking system as a cause of Sebastian Vettel's Australian Grand Prix retirement.
The Italian manufacturer says the German's exit in Melbourne while leading from pole position, was not caused by the brake failure.
It added the Formula One team had confirmed to the company that the 22-year-old retired after the torque drive between the front left axle and wheel was lost.
Vettel has started both races this season from pole position but has yet to finish on the podium after suffering problems while leading.
After Sunday's race in Melbourne he said he'd seen sparks from the left front wheel and felt huge vibrations building up.