hello, this is my first post here, as i just bought my 1974 260z!

i looked on this forum and others for an answer to this and have decided to join this forum as it seems to be a bit more mature than some others.

anyway.... i'm not new to cars, but am new to this Z, so i figure i would ask before diving buying parts.

symptoms;

1 car revs to about 3k rpm when not moving and brake pedal is depressed.

2 no power brakes(barely stops)

if this was a car i was more familiar with, i would guess compromised diaphragm in brake booster.

thoughts?

thanks in advance

-the wombat

Yup, bad booster. These cars aren't all that unusual, most things work much like they do on other cars.

A brake booster is a brake booster, doesn't matter what make. A hole in the diaphragm is a good guess. Do some searching on here on the vacuum booster and reaction disk, you will find the answer.

thanks for the quick response!

i figured as much, but better to ask than not to, right?

I've seen that happen when someone put the one way vaccum check valve in-line - backward. I've seen that happen when 38+ year old vaccum hoses cracked lengthwise. Just make sure you have good vaccum supplied to the booster first.

Does the car have a new looking Brake Master Cylinder by chance? Inproperly installed/adjusted - the push rod can stop short of applying full pressure as well.

FWIW,

Carl B.