Brake Booster Noise
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Mountain Pass
Joined: Apr 2002
Posts: 230
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Brake Booster Noise
On my 71 F-100, I will hear a his from the firewall whenever I press the brake pedal. If I really stand on the brake pedal, the his will stop. It sounds like a leak. And I've never heard anything like this on any other power assisted car I've owned.
I also don't think there is a vacuum leak, at least not a net vacuum leak. The engine's idle doesn't seem to be affected. Most cars that I've seen with power brakes will show obvious rough idle when a small vacuum line is open and they won't hold an idle or even start if the brake line is open. Here there is no change, however I might check that claim with a vacuum gauge in the near future.
Does any one else here hear noises like that? Any opinions?
I also don't think there is a vacuum leak, at least not a net vacuum leak. The engine's idle doesn't seem to be affected. Most cars that I've seen with power brakes will show obvious rough idle when a small vacuum line is open and they won't hold an idle or even start if the brake line is open. Here there is no change, however I might check that claim with a vacuum gauge in the near future.
Does any one else here hear noises like that? Any opinions?
Post Fiend
Joined: Feb 2000
Posts: 5,130
Likes: 8
From: Brea CA
Brake Booster Noise
It's your booster that's leaking. It will eventually get worse and start affecting your idle. You may hear a little wisp when you first apply the brakes, that's normal but if it continues with the brakes applied, start saving for a rebuilt unit.
Barry
Barry
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Mountain Pass
Joined: Apr 2002
Posts: 230
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Brake Booster Noise
I was listening to car talk and they indicated that a hissy booster is probably bad regarding a call from someone.
They suggested trying a test. With the engine off, pump on the brake pedal 25 or thirty times and hold your foot on it. It should be hard as a rock and the pedal should not be too depressed.
Start the engine, if the pedal does nothing, doesn't give or depress more, then the booster's bad.
Mine's bad according to that.
And even if it's not, a loaded booster is not even $100 soProfanity Removed.
Thanks
They suggested trying a test. With the engine off, pump on the brake pedal 25 or thirty times and hold your foot on it. It should be hard as a rock and the pedal should not be too depressed.
Start the engine, if the pedal does nothing, doesn't give or depress more, then the booster's bad.
Mine's bad according to that.
And even if it's not, a loaded booster is not even $100 soProfanity Removed.
Thanks
Post Fiend
Joined: Feb 2000
Posts: 5,130
Likes: 8
From: Brea CA
Brake Booster Noise
Click and Clack, they crack me up!
That's a good test. By pumping the brakes with the engine off, you are releasing all the residual vacuum in the booster. After all the vacuum is gone, it should feel like manual brakes. When you start the engine with your foot on the brake, the vacuum builds back up and your pedal should drop down some and feel like power brakes again, but without all the hissing.
Barry
That's a good test. By pumping the brakes with the engine off, you are releasing all the residual vacuum in the booster. After all the vacuum is gone, it should feel like manual brakes. When you start the engine with your foot on the brake, the vacuum builds back up and your pedal should drop down some and feel like power brakes again, but without all the hissing.
Barry
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