McLaren team boss Andreas Seidl says that they still don't know what caused Lando Norris' problem that put him out of Sunday's Canadian Grand Prix.
Norris had been running solidly after a good battle with Max Verstappen in the opening laps before he had to pull over at the end of the pitlane, with his brakes red hot.
It was unclear at the time what had caused the problem, and Seidl says they are still investigating, telling Motorsport.com: “We had an overheating rear with a mechanical failure, but we still have to find what the reason is, we don’t know yet.
“We just saw that temperatures suddenly went up, the brakes went long as well, and we saw that he was going wide, which is where it started to happen.”