From the booster, to a vacuum source on the engine.
A bad brake booster will cause a vacuum leak, result in poor braking, and even poor engine performance. The brake booster has a large diaphragm which can fail and leak.
You may have a bad power brake vacuum operated booster.
On modern vehicles the brake system is enhanced by a vacuum operated "booster". This makes the brake pedal softer and more responsive. When the engine is turned off the engine no longer produces vacuum to supply the booster so the pedal gets hard.
Perhaps a vacuum leak check power brake booster for leak and also inlet check valve on booster
no.
It could be a leaking vacuum hose to the power brake booster or the membrane in the booster could have a hole. When the brakes are applied, the booster is opened to the engine vacuum via the hose. The vacuum leak would then increase, causing the engine to stall.
The power brake booster is leaking vacuum and that makes the engine die when the brakes are applied. Replace brake booster.
That would be the power brake vacuum operated booster.
my 67 was on top
With engine off--pump brake until all vacuum is exhausted With foot on brake start vehicle--brake pedal should drop
Normally the vacuum line from a brake booster goes to the intake manifold of a gasoline engine. Sometimes other lines will be tied in to feed vacuum to cruise control pots or 4x4 actuators, but the main hose will be larger.