'99 JGC Hissing Sound...

[ninpo23]

Trying to isolate this issue on my '99 JGC 6 cyl, this morning when I started up my truck, I am hearing a larger hissing sound coming from the brake pedal and when I press down on the brake pedal, the sound goes away and when I am driving with foot on gas, I can bearly hear the hissing and then touch brake pedal it goes away. I look but cannot truly isolate the issue, any ideas where to look?

Thanks,

Ninpo

[Bob D.]

Under hood Vacuum leak. Check the vacuum line going to power brake booster and the booster itself.

[ninpo23]

Thanks, I will....I am thinking the possibility of the master cylinder going to?

[ninpo23]

Hello,

Where would the vacuum line for power brake booster be locatred at?

Thanks,

Ninpo

Originally Posted by Bob D.

Under hood Vacuum leak. Check the vacuum line going to power brake booster and the booster itself.

[Bob D.]

It's right on the booster, and goes to the intake manifold.
Is this a trick question?