[Mr.Tugtug]

With -28 feels like temperature car parked outside for 8 hours, with brake pedal stiff, press start, started like normal.
Here's the concern:
What's the chance of building pressure in brake booster if you leave the car for a week?

 

[sparkydave]

The check valve on the brake booster accumulator might not be sealing well and bleeding down. Once you start the car, vacuum (not pressure) builds up quickly and you have brake assist in less than second.

 

[Mr.Tugtug]

Thanks for reply:
And if we don't have a chance to start because
we've gone for a week or so and temperature goes down to this point, for how long it might hold the pressure before or just might it burst?

 

[Mr.Tugtug]

And surprises us that our brakes are not holding car while approaching to an intersection or a light stop.

 

[sparkydave]

The check valve and accumulator holds vacuum if the engine stops, so you have some reserve to stop without having to stand on the brake. If the engine is running, the check valve doesn't have a lot to do because the vacuum is available. If you're really worried about not being able to press the brake to start it, have the check valve fixed.

 

[tinylo]

that check valve failed on me on a really cold winter day a few years ago, and the boost was lost and we had only manual brakes. Replaced the hose assembly and solved the problem.

 

[Mr.Tugtug]

Thanks, that's good to know.
Actually, some of us here have had been experiencing this also which raise a concern because if the brake booster accumulator can't hold anymore what's the chance of bursting if parked at the airport for a month with -28 feels like temperature.

 

[Slvr7]

It's not building pressure, it's loosing the vac. it's supposed to be storing. There is zero chance it will burst with sitting for any length of time. It needs a check valve or a booster, possibly a master leaking that caused the booster to leak vac.

 

[Mr.Tugtug]

Can you elaborate more to us why this one happens only during cold weather and some actually can't even start the car because of stiff pedal. Thanks

 

[Slvr7]

I've had customers have this issue year round. However, cold makes things shrink and not seal. Seal in the check valve, between the master and booster, seals in the booster are all subject to leak and loose the vac. stored in the booster after the engine is turned off. If the master leaks brake fluid into the booster, that will attack the rubber and cause leaks as well.