2000 Buick Park Avenue Brake Vacuum Leak

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Joined: Thu Dec 13, 2012 1:27 pm

2000 Buick Park Avenue Brake Vacuum Leak

Unread post by BuickPA2000 » Thu Dec 13, 2012 1:51 pm

When I depress my brakes I hear a wooshing sound as long as I hold them down and while holding them down they slowly leak down to the floor. I am not getting a rock solid lock' em up brake process. The wooshing sound appears to be in the area of the booster. All brakes (disc) are completely new just 3-4 months ago. I have had no issues with the brakes.

When we changed the brakes they were well bled. About once a week my ABS indicator light will come on when I back out of my driveway and then go out shortly after. I have checked the vacuum from the engine to the booster and no discrepancies noted. It was suggested to me to run the car, turn it off and then pull the vacuum line from the booster and listen for a vacuum sound. I did this and yes I got a vacuum sound so I am thinking that the booster diaphragm is intact.

My MC is not losing any fluid. My thoughts are a 1. failed booster, 2. an internal leaking MC or 3. an ABS module issue (there was a recall back in the day for the "Brake Hydraulic Control Unit" (also was referred to as "Internal Leaks in the ABS hydraulic modulator") I have had GM cars for 30+ years and have never had this problem. Since I am out of work I cannot do shotgun maintnenance so I appreciate any help I can get. Thank you.

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Re: 2000 Buick Park Avenue Brake Vacuum Leak

Unread post by ProTech » Thu Dec 13, 2012 11:40 pm

Well, the 'wooshing' sound is a dead giveaway of a bad brake booster, whether is checks ok or not. Especially if it keeps doing it while your foot is applied to the brake pedal, it's basically just letting the vacuum pass right through it, hence the poor pedal feel.

I'd recommend replacing it, or at least finding that vacuum leak to verify.

The ABS problem is most likely something completely different, and usually just a bad wheel speed sensor or wiring harness.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

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