[3dplane]

Hi herberpower!

I have to ask! What's a deadlock?

If you shut the engine off your car SHOULD still provide brake assist for at least 2 or 3 brake pedal applications before the vacuum runs out of the booster!

Unless it has a leaking vacuum booster or a check valve somewhere in the system!
( I don't know if your car has a vacuum pump or what kind of system it has)

It also sounds like your car could use a new alternator if 800 rpm is not enough to charge the battery. Sometimes a diode (or diodes) will fail, killing a phase in the alternator so it will only start charging at a higher rpm!