Aston Martin CEO Otmar Szafnauer has admitted the team doesn’t know why it suffered a host of brake-related issues in the lead-up to the Emilia Romagna Grand Prix.

On their way to the grid, Lance Stroll and Sebastian Vettel’s rear brakes ignited and melted ahead of the race.

Aston Martin managed to repair Stroll’s brakes so he could make the start, while Vettel was forced to start from the pit lane as the repairs weren’t completed in time.

The delay in Vettel’s repairs meant his tyres weren’t fitted before the five minute deadline and thus he was awarded a 10-second stop-go penalty as a result.

When asked to explain what caused the brake issues ahead of the race, Szafnauer explained: “I was just in the debrief and we still don’t. We’ll get all the data for the laps to the grid. What happened was, we overheated the rear brakes and the laps to the grid weren’t at the normal pace that we usually go, so we didn’t get the airflow. 

“But we’re aware of that, and even with that, the settings are such that they shouldn’t have caught fire. We overheated them but we don’t know why or how.”

Stroll went onto finish eighth, while Vettel retired on the penultimate lap after gearbox issues plagued his afternoon.

Szafnauer revealed Vettel was suffering from a gear sync issue every time he crossed the start-finish straight.

“There’s some indicators,” Szafnauer said. “It seems like every time we pass the start-finish line we lost the synchronisation of the gearbox. So there’s some clues but we still don’t know why.”

Leaving Imola, Aston Martin sits sixth in the constructors' championship on just five points.

Szafnauer is confident the Silverstone-based outfit can find significant performance gains in the coming races.

“We’re still working hard at that,” Szafnauer added. “It seems like we’ve got to look really hard at one-lap pace. It looks like race pace was a little bit better, although we had drying conditions here, wet conditions and people on different tyres, so it’s hard to know. But I think Lance did a brilliant job to come home seventh from where he started in a tough race. 

“Unfortunately, Seb had the gearbox issue and also the penalty, so it didn’t really help. But we’ll look through all the data and we’ll work hard to pull it back.”