Snake under my foot (brake hiss)

[Phacade]

Just looking for a little help here with my '75 280Z. I was coming home yesterday and on the last turn before my house, I pressed the brake. My petal starts going down slowly but down further than it has before and makes an audible hiss when pressed. I checked the fluid and both fluid conisters on the master cylinder were half full. I topped off and (I know silly but had no choice) drove to work this morning. It stops. Kinda. But takes me 4 times the distance to stop and makes a hiss whenever pressed.

Master cylinder?

Master Vac?

Line?

Help.

[Rob]

Sounds to me like the diaphragm in the booster is kaput. If the line was leaking you would get a constant vacuum leak and the motor would idle high. I think it's possible to service these yourself but I've never actually needed to do it.

[Phacade]

I posted this here and a few other places and that was the general thought. Sunday I switched out both the booster and the master cylinder (just to be safe). Works great, I can stop; and thats a good thing.

[Rob]

Yes, being able to stop is a good thing!

Years ago I had total brake failure (handbrake didn't even work as it was hydraulic) in my rally car while driving to uni. As I didn't want to leave my car on the side of the road I decided to keep going, and learned the meaning fear as I slowed the car down with the gearbox, and stopped it by turning off the engine and gently using the clutch as a brake. Stoopid!:eek: