Brake Area Producing Hissing Sound

Rob_Supra87

87NAPWR
Aug 3, 2008
278
0
16
Millbrae
So while driving I will press on the brake and hear a loud hissing sound and the sound will even stay going on after I let off on the brake entirely, help? Brake fluid is at "minimum" and I plan on buying some when I go out, is that the fix?
 

MA70L-BJMVZA

New Member
Dec 8, 2010
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Virginia
I don't think brake fluid is going to help. The "hissing" noise you mention, it sounds like a vacuum leak from the brake booster. Is noise loudest inside car or under hood? How about with engine running or stopped?
 

Rob_Supra87

87NAPWR
Aug 3, 2008
278
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16
Millbrae
The noise sounds like it is coming from the wheel well of the passenger side, I only hear it when running, for example I will be going 35 then press the brakes to slow for a stop sign then after i let go of the brakes and the car is slowly drifting to a stop I will hear it
 

stevenr816

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Feb 12, 2007
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Hissing as in maybe the warning tab on the brake pads? Have you checked all your pads for how much material is left on them?
When you press on the brakes, the tab rubs usually until you take off again until the pads loosen back up.
 

MA70L-BJMVZA

New Member
Dec 8, 2010
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stevenr816, I think you nailed it. wear indicators are rubbing the rotor. worn pads would also explain the low brake fluid level in the reservoir
 

stevenr816

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Feb 12, 2007
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MA70L-BJMVZA;1648813 said:
stevenr816, I think you nailed it. wear indicators are rubbing the rotor. worn pads would also explain the low brake fluid level in the reservoir

if you havent added any since a new pad change it should go right to the top. but do 1 at a time or it usually over flows
 

destrux

Active Member
May 19, 2010
1,183
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PA
Yeah, you really should only ever need to add brake fluid if you:

1. Have a leak
2. Took apart something that let brake fluid out.
3. Are bleeding the brakes.

Otherwise the brake fluid should be full with new pads on all 4 corners and the reservoir should hold exactly enough fluid that the "low fluid" light comes on precisely when the pads are all worn out. Pushing the pistons on the calipers back in should refill the reservoir to the full line. Some people prefer to push the pistons back in with the bleeders open and put fresh fluid in the reservoir to fill the system back up though, since brake fluid should be changed every year or two anyway.
 

Rob_Supra87

87NAPWR
Aug 3, 2008
278
0
16
Millbrae
yeah thats possibly it but now while driving and not even pressing the brakes at all it will be squealing under the wheel wells nonstop and it only stops when I press the brakes lol