Red Bull continued to struggle on the first day of the second Formula One preseason test.
The reigning world champions spent the first four hours at the Bahrain International Circuit working on the car behind closed doors.
Live coverage of the test on Autosport's website noted that there was a lot of cutting and grinding sounds coming from the garage as the team worked on the rear of the car.
The team's Twitter feed attempted to play down the delay:
Slight delay folks, the team's still fitting some parts. We've fired up and are hoping to be on track shortly. More updates to follow.— Red Bull Racing (@redbullracing) February 19, 2014
When the car finally took to the track, world champion Sebastian Vettel was at the wheel. Determined to make up for lost time, he didn't spend long trundling around at low speed and set a best time of 1:40.224.
Though it was almost three-and-a-half seconds slower than the best of the day, set by Nico Hulkenberg for Force India, the time was good enough for fifth-fastest. He could have gone quicker, but aborted two better laps.
But while the speed was reasonable for a car which essentially missed the first test, the reliability was not.
Vettel managed just 14 laps before stopping out on the track:
In the picture tweeted by Sky Sports F1, a huge flat spot is visible on the rear left tyre of the RB10, and the front right doesn't look healthy either. Smoke was also seen coming from the rear of the car and Vettel was taking no chances, arming himself with a fire extinguisher.
It was later revealed a rear brake problem caused the spin. They'll probably prefer that to engine issues, but it highlights yet another thing which needs looking at and fixing.
The stoppage came on the fourth lap of a stint and means the RB10 is yet to manage more than three laps in succession.
By contrast McLaren, Mercedes, Ferrari, Sauber and Force India all did more than 60 laps. And even Caterham, using the same Renault engine as Red Bull, did 68.
But curiously, the other Renault teams—Toro Rosso and Lotus—struggled even more than Red Bull, managing just eight and five laps, respectively. The French manufacturer clearly still has issues to resolve.
Red Bull's odds of winning the constructors' championship are now as long as 3-1, according to Oddschecker.
Unless they can find a very quick fix, even that looks like poor value.