Vacuum and Brakes

[Stallion]

What does the vacuum have to do with brakes and their performance? Where's the relation?

[Stallion]

I know about the vacuum booster, but I did not know where the vacuum came from. Obviously the source would be the engine vacuum.

But what happens if you are running at a high RPM with little vacuum? Would your brakes fail you then?

Thanks!

Stallion

[MaineShark]

Or you convert to a hydraulic booster

They use a pressurized nitrogen cannister to store enough braking energy for a couple stops, if you lose your power steering belt, or something. Then, once you bring the system back up to pressure, it re-charges the reserve cannister

If you want to feel the reserve on your vacuum brakes, shut the car off after running it, then press the pedal. It moves easy, like usual. Press it a couple more times, and you'll see what happens as the vacuum reserve is used up, and you have not assist. It's not a bad thing to know what it feels like, just in case your engine ever stalls while you're driving it, and you have to stop without the assist.

The loss of engine vacuum in certain situations is certainly one issue. As is the fact that some very aggressive cams produce very little vacuum, to begin with. But the biggest "day to day" thing that I don't like about vacuum brakes is their inconsistency. Since they depend on engine vacuum, which varies constantly, the braking is never consistent

Joe

[Stallion]

That is weird. So you are telling me that for all those people out there with Corvettes and no power brakes, this is what they feel!?

Thanks, I understand!

Stallion

[JohnZ]

Those of us without power brakes just push harder; if you also happen to have a really heavy-duty clutch, then the muscles in both legs will be equally developed and you won't walk funny

[bossvette]

Those of us without power brakes just push harder; if you also happen to have a really heavy-duty clutch, then the muscles in both legs will be equally developed and you won't walk funny

[MagikDraggin]

Originally posted by Stallion
That is weird. So you are telling me that for all those people out there with Corvettes and no power brakes, this is what they feel!?

Thanks, I understand!

Stallion

No, it's not quite THAT extreme. Non power brakes do require more user effort in pedal pressure, but nothing like a power system that has lost its vacuum.

Vettes with long duration cams also experience a shortage of vacuum to the booster; especially right after starting the motor up and immediately driving off......that first stop can sometimes be a bit scary, until the vacuum supply builds up.