https://www.racefans.net/2018/07/01/mer ... e-upgrade/“We had a hydraulic leak that was linked to the steering on Valtteri. And we had a drop in fuel pressure on Lewis’s car which was linked to the fuel system. This is the current understanding. So no regrets on introducing the engine.”
Fuel pressure and steering hydraulics, different problems. Valtteri's car sounded like gearbox was dead, is there only a single hydraulic system on an F1 car?