4 replies to this topic

[Neil7744]

What does the vac pipe between the inlet manifold and brake servo do exactly?

[wassupcrew]

it transfers the vaccuum from the inlet manifod to the servo

[Ethel]

It creates a vacuum |


When you're on overrun, with the throttle shut, as you would be when braking; the suction created by the engine it transmitted to the servo via the pipe. The servo contains a big diaphragm, usually both sides of it are connected to the pipe. When you push the brake pedal you close a valve, isolating the 2 sides and open the rear side to atmospheric pressure the pressure difference that now exists across the diaphragm pushes it, and the master cylinder, harder than your foot alone.

[Neil7744]

i gathered that...but why dows the brake servo need vacuum?

[Neil7744]

ahh right, like an actuator.