View single post by Jensenman
 Posted: 04-28-2009 01:02 pm
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Jensenman

 

Joined: 04-14-2005
Location: Columbia, South Carolina USA
Posts: 156
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The brake vacuum booster probably has a leak. When you push the brake pedal, this opens a vacuum valve inside the booster so that engine vacuum can pull the diaphragm forward (that's what generates the 'boost'). If the valve does not seal properly, it's the same as a vacuum leak on the intake manifold. Sometimes it's audible inside the car as a hiss. FWIW, every so often mine does the same thing and I can actually hear a 'squeak' noise from the booster but it still works fine. So I'm gonna leave it alone for now. :-)