Would someone be willing to explain the vacuum system?

[Uhohspaghettios]

My (possibly extremely wrong) understanding is the vacuum is created in the intake manifold. Hose lines coming from that "transport" the vacuum to the brakes, climate control, and 4 wheel drive (if properly functioning). So my brakes booster (06 Expedition Limited) has a check valve with three hoses. One hose goes from the black part of the check valve to the passenger side, that transfers the vacuum that affects air coming out of the proper vents vs. defrost? Two hoses come from the lightly yellowed part of the valve. One goes to the air filter box and one goes to a metal pipe that looks to go behind the engine. I don't really understand the point of the one going to the air filter box but the other one is maybe what should transfer the vacuum to the brake booster?


Many thanks if anyone has the patience to read through that and clarify

 

[Uhohspaghettios]

 

[Uhohspaghettios]

It does. The bottom rubber hose goes to a metal tube that goes to the back of the engine and seems to become a rubber hose with a ninety degree angle that can just barely be reached from under the driver's side to push it on a little metal vacuum port

 

[BMW2FORD]

A gas engine only has vacuum in the intake manifold at light to normal throttle. On heavy throttle, there is very little to none at full throttle. When at really heavy or full throttle, there is a ton of air pulled through the filter and tubing in front of the throttle plate so there is some vacuum here but only at that time and not as much as manifold vacuum at light throttle. It was referred to as ported vacuum in the carburetor days. The valve in the booster senses which is greater and uses what it can.

 

[Uhohspaghettios]

Thank you much!