Mercedes team principal Ross Brawn said rival teams can challenge the legitimacy of its suspension system if they wish, even though the sport's policing procedures are in a flux due to the lack of a governing Concorde Agreement.F1 is currently racing in the absence of a Concorde deal - a confidential agreement between teams and the sport's governing bodies about F1's rules and commercial arrangements - and that had put into question how teams can go about challenging any perceived rule breaches.Prolonged negotiations on a new Concorde are proceeding slowly."There's speculation but nobody knows what our suspension system is and from what I know, it's not uncommon throughout Formula One," Brawn said. "I don't think it's controversial, I don't think there are any issues."Active suspension, when controlled by electronics, is banned under F1 rules, but there had been speculation that Mercedes had found a way around the rule by using a hydraulically controlled system.A possible clue was provided during Saturday's practice session at the Chinese GP when Nico Rosberg said over his radio that "something's broken in the springs" and the team later identified the problem as a hydraulics issue.NO BIG DEALBrawn said, even in the absence of a Concorde deal, any challenge from rival teams would proceed in the way they had in the past."The situation would be exactly as it had been before; somebody would go to the stewards, complain, they'd look into the matter, it would be resolved one way or another," Brawn said."If people weren't happy with that, then it would be appealed and go to an appeal court." Stay with Wheels24 for the 2013 Formula 1 season – fresh reports every day.