McLaren discovered the existence of the device from open-source documents that contain information on each team’s cars that have to be submitted to the FIA and to which all teams have access.
Red Bull have agreed with the FIA to make changes to their car for a future race, expected to be the Brazilian Grand Prix in two weeks’ time. The detail of these modifications has not been revealed.
Red Bull say the device is “inaccessible once the car is fully assembled and ready to run”.
But the parc ferme period extends from the start of qualifying to the end of the race, and teams are allowed to assemble and disassemble their cars during this period, as long as they are not modified.
Brown said: “I have heard that you can’t adjust it when the car is fully race-prepped, but the car isn’t always fully race-prepped when it’s in parc ferme. That needs to be unpicked.
“Why do you need to put a seal on something that you can’t access? So I still have questions.”
He added: “I have confidence the FIA will resolve the issue. I understand they are having to modify and change their car for upcoming races. Our questions are a bit more around what has historically happened.
“If it’s used in an inappropriate manner, then it is definitely a performance advantage. If it’s not, then there is no performance advantage and that’s what we want to discover.”
Red Bull team principal Christian Horner told Sky Sports: “Every car has a tool that they can adjust the front of the bib, what we call the front of the floor being called the bib.
“Ours is located at the front of the footwell. It’s been there for I think for over three years, you’ve got to have the pedals out, other panels out and pipework out to be able to get to it.
“It’s like any other adjustment on the car, it would be easier to adjust the rear roll-bar than it is to get to that component. It’s all part of the packaging in the front end of the chassis.”
FIA single-seater director Nikolas Tombazis said: “At the previous race, it was pointed out to us that certain designs could allow a change of the height of the front of the car, which some people call a bib, in parc ferme, and we didn’t have any indication or any proof that anybody was doing something like that.
“That would be clearly illegal under parc ferme regulations.
“So we said from this race onwards, there must be no possibility to do such thing at all. If there’d be a design that allowed a quick change of that height, then it would have to be sealed so they wouldn’t have access in parc ferme, and all teams have adhered to that and as far as we’re concerned, everything is under control.
“It’s certainly not a story from now on. We’ve done all that’s needed to stop there being any accusations. And of course, it is a title championship and people get rather excited about each other’s cars.”
Red Bull in turn have raised questions about McLaren’s rear wing.
These stem from modifications that McLaren chose to make following consultations with the FIA after Red Bull raised concerns about how much it was flexing during the Azerbaijan Grand Prix.
Brown said: “Our rear wing has passed every single test. We have had to make some small modifications as have some others. So that’s a non-issue.”
Brown also criticised Red Bull motorsport adviser Helmut Marko for comments he made about McLaren driver Lando Norris.
Marko said that Norris, who has narrowed the gap on Red Bull driver Max Verstappen in the championship to 52 points with six races to go, had “some mental weaknesses”, adding: “I’ve read about some of the rituals he needs to do to perform well on race day.”
It appears Marko was referring to remarks Norris made at the Italian Grand Prix when he described his nerves on race days and said he “barely eats anything on Sundays. I struggle to drink on Sundays. Just because of nerves and pressure.”
Brown said he was “disappointed but not surprised” by Marko’s remarks.
“Lando has been kind of an ambassador for mental health. Toto [Wolff, the Mercedes team principal] has spoken about mental health, so I think it’s a serious issue that we’ve tried to talk about and bring to the forefront.
“Poking at that situation I think is pretty inappropriate and kind of sets us back 10-20 years.
“It’s all fun and games in how some people go racing and what tactics they use from a sporting perspective, but I thought that one was in pretty poor taste.”
