Hissing break peddle

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Nov 25, 2001 | 09:17 PM

C Davis

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Hissing break peddle

[updated:LAST EDITED ON 25-Nov-01 AT 10:20 PM (EST)]Hello everybody, this is my first post. I have just rebuilt the 302 in my 83 full size Bronco XLT. Everything is just about perfect except for one thing. Whenever the break peddle is not applied there is a hissing sound, and whenever the breaks are applied, the sound goes away. I thought it could be the break power booster, but it seems to me it is more likely a vacume leak somewhere, and the power booster could be taking up the access vacume when stepping on the break peddle. I have checked everywhere I can think of with a water hose to my ear, and even though I did find a couple vacume leaks, the hissing is still there. Could someone please clue me in on this nagging problem?
Thanks,

C.Davis

Nov 25, 2001 | 09:45 PM

Mil1ion

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Hissing break peddle

Hissing BRAKE PEDAL huh?

Things to check with someone to help:

While someone steps on the BRAKE PEDAL & you have your head under the hood,give a listen around the Check Valve on the Brake booster,the vacuum tree on the manifold where all the hoses are connected, transmission vacuum line.
If you can't hear anything hissing.
Then,after getting the vacuum built up ,shut the truck off,then have that person again slowly press the BRAKE PEDAL in and you might be able to hear a difference and locate the leak.

Dennis

78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles

Nov 26, 2001 | 02:01 AM

C Davis

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Hissing break peddle

Dennis,
After I began spelling "Brake Pedal" correctly, it quit hissing at me. Just kidding, I'll try your suggestions in the morning.

Thanks,
C. Davis

Nov 26, 2001 | 12:59 PM

adelyser

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Hissing break peddle

To check for a vacumm leak, spray some carb cleaner at the vacumm connections, and if there is a leak, the engine speed will drop when you spray the cleaner.

Nov 26, 2001 | 11:05 PM

JBronco

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From: Loveland, CO.

Hissing break peddle

Someone suggested this to me to help me find a minor vaccum leak on my a/c vent controls. I haven't tried it yet, but you should check the vacuum canister for leaks. It's the thing that looks like a coffee can painted black. The person who told me this had a leak on the seam of the canister. They fixed it with JB weld and the problem was solved. He said that he pushed on it while the engine was running, and it caused it to make the noise which helped him determine the problem. I haven't bothered trying this yet because my problem is very minor, but one day when I'm bored I will go out and look at it. But you may as well check your canister and the hoses leading to it.

Dec 9, 2001 | 07:30 PM

8996EBBroncos

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From: Eastern, NC

Hissing break peddle

Most likely, you're gonna have to get a new brake booster.

Dec 13, 2001 | 03:34 PM

flatspin

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From: Greenlawn USA

Hissing break peddle

Same thing on my truck. Figured the booster was shot so I replaced it. Just the same.

I am on my way out to look at the vacuum reservoir now. Sounds logical.

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Dec 16, 2001 | 05:38 PM

Mil1ion

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Hissing break peddle

That's the *Check Valve* I mentioned in an earlier post.

Dennis

It's Almost Time Everyone.

https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=314&.jpg

78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles

Dec 17, 2001 | 05:51 PM

#10

RRL78

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Hissing break peddle

The check valve you mentioned is on the brake booster, the one i'm reffering too is on the top of the brake peddle, inside the truck. If the bronco's even came equiped with one. Rob

Dec 17, 2001 | 05:56 PM

#11

Mil1ion

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Hissing break peddle

Isn't that the Cruise control shut-off valve?

Dennis

It's Almost Time Everyone.

https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=314&.jpg

78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles

Dec 22, 2001 | 07:09 PM

#12

RRL78

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Hissing break peddle

I'm not really sure, mine was hissing and every time i hit the brakes it would quit. I took one hose off and stuck it too a bolt and, i don't hear any more hissing. All i know is my cruise control works great, and my brakes work great. Anyway, i hope this fella gets the problem fixed. Have a Merry Christmas. Rob