As long as there are no vacuum leaks it should be able to hold a vacuum for days. Same holds true for an ICE.
If you leave your ICE sitting parked for a couple of days, and then you depress the brake pedal to start the engine, the brake pedal will still go down easily because it still has vacuum. But if you pump the pedal a few times before starting it'll build up resistance.
I'm guessing that if you press your Tesla brake pedal a few times the pump noise happens again? I haven't taken delivery yet so I can't test.
BTW, another fun fact... ICE only generates vacuum pressure when the throttle is closed, which is the normal case when you're braking. If you hold down the throttle and the brake pedal, you'll lose vacuum and the braking will become more difficult if you repeatedly pump the pedal-- making a car more difficult to stop if the throttle gets stuck (Toyota?)
If you leave your ICE sitting parked for a couple of days, and then you depress the brake pedal to start the engine, the brake pedal will still go down easily because it still has vacuum. But if you pump the pedal a few times before starting it'll build up resistance.
I'm guessing that if you press your Tesla brake pedal a few times the pump noise happens again? I haven't taken delivery yet so I can't test.
BTW, another fun fact... ICE only generates vacuum pressure when the throttle is closed, which is the normal case when you're braking. If you hold down the throttle and the brake pedal, you'll lose vacuum and the braking will become more difficult if you repeatedly pump the pedal-- making a car more difficult to stop if the throttle gets stuck (Toyota?)
