Worth a try....Really odd hissing noise.

[BoOsTeD_RB26]

Hey people,

Well this is really starting to pi$$ me off. There is a hissing sound (sounds like an air leak of some description), coming from the drivers side footwell, right near the pedals.

It will hiss whilst in vacumm and the hissing goes away once the car starts to make some boost. Also, the sound goes away when the clutch pedal is pushed in about half a centimeter (not actually engaging the clutch).

I have checked the hoses for the boost gauge in the car as well as the boost controller and the lines are perfectly fine.

I'm stumped as to what it may be.

Anyone had any similar problems?

Cheers

[ib6ub9]

I got the same problem on the drive from canberra up to brisbane. I have been told its more likly to be the diafram in the clutch booster or something. I am not a mechanic.. But if you feel the rubber behind the clutch you should be able to feel it "breathe" as i like to call it, I am waiting till i get back to canberra as i have been assured from my mechanic it will be ok, Just the clutch is heavier...

Good luck, If you hear any different, Please let me know, Second and third opinions never hurt.

Cheers

[horn]

Try blocking/clamping the vacuum hose to the clutch booster,if the hiss stops its the booster.

Then unbolt the clutch master cylinder and check the rear seal for leaks/fluid.

A leaking rear seal will let brake fluid get sucked into the booster and ruin the booster seals and give a vacuum leak. Both the booster and master cylinder will

require overhauling.

flushing the clutch and brake fluid every 2 years will stop this from happening.

hope this helps. :how:

[rb25_sil80]

Didnt think there was such thing as a clutch booster. If your talking about the brake booster then yes definately. another thing is, if your brake booster fills with brake fluid, this will get sucked into your motor through that vacuum hose and hydro lock your engine.

This is not good, its happened to me, totally destroyed a brand new engine. Brake fluid does not agree with engine parts !

[BoOsTeD_RB26]

In the end it was the Clutch Booster. I think that only the GTRs have the sort of "hydraulic" set up when compared to GTSts and the like. The booster is being replaced on Thursday so I'll post up if this has fixed it or not.

Thanks everyone for their help!