brake booster? Whats the little tube do?

[s13gebala]

i was "trying" to bleed my brakes today an found out i have leaks almost on every wheel after changing the lines, after i made them tight as hell i was able to carry on.

i have a question though, this might affect my brake bleeding process and im not quite pleased, but WTF is this and where does it go and what does it do?

picture- the little metal tbe on the black booster circle cylinder that has a tube attached to it, whre does it lead?!

[hai1206vn]

it's a vacuum hose that leads to a nipple on the block. If you don't connect it to the block, the engine wont run properly and stall

[s13gebala]

can i bleed the brake system and just leave the valve open, or do i have to have the engine block in the bay to bleed the system

[johnnyballs180]

i think as long as the hard lines are hooked up, you should be fine.

[s13gebala]

ok, because when i compress the brae pedal, air excapes from the tube

[johnnyballs180]

well, from what i understand, a gasoline engine running creates vacuum. that big rubber tube is connected to a vacuum source, and when the engine is running, the air inside the vacuum booster gets sucked out. the vacuum causes a diaphram inside the booster to move to help push the piston that goes to the brake master cylinder.

i'm pretty sure you can bleed the brakes as long as you have the hydraulic hard lines for the brakes hooked up (and you have brake fluid, of course).

when you press on the brake pedal, with or without anything hooked up, you move that diaphram, which pushes air out those vacuum tubes.

you should still be able to use the brakes without the vacuum tube hooked up. you ever tried braking when the engine's off? really hard, right? that's just because there's no vacuum produced by the engine to assist.