Upgrading Brakes!!! novice questions

[cheddarcheese]

why is there a vacuum hose that goes to the big black round thing with the master Cylinder in the middle? what happens if you don't have this blah blah blah?



cheers
andy

[sinister polo]

i think you will find that if it isnt connected your brake pedal will go solid after a few pumps!

[Alexiskayak_7]

why is there a vacuum hose that goes to the big black round thing with the master Cylinder in the middle? what happens if you don't have this blah blah blah?



cheers
andy

Start your car, roll it (20 miles) then turn of your engine, give a few bumps on the pedal, you'll see that after 2-3 bumps you won't have brakes.
That black drum is a servo, it uses vaccum from the engine (inlet manifold) and it boosts up the pressure in the master cylinder, so you have effective braking...

[hayesey]

it's a big diaphragm which uses vacuum pressure to help you press the brakes.

if you remove it (like a mk2 polo) the brakes will require you to press them harder but the benefit is that you get more feel through them.