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Hi Everyone,

I am new here so please be gentle with me....

I have noticed that sometimes when I apply pressure to my brake pedal there is a hissing sound like there is air coming out somewhere near the brake pedal. It also seems like the brakes are a little softer and/or more delicate. Does anyone know what this could be???

Also, the sensor saying that the seat belt is not fastened does not go off even when all the seat belts are attached. Is it a possible connection isuue either in the wiring or perhaps the seat belt buckle?

:roll:
Thanks
Brad
 

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canadadude said:
...sometimes when I apply pressure to my brake pedal there is a hissing sound like there is air coming out somewhere near the brake pedal. It also seems like the brakes are a little softer...
Welcome to the forum.

The hissing sound could be an air leak at or near the brake booster, which is on the other side of the firewall from the brake pedal, inside the engine compartment.

The brake booster has a diaphram inside, which works against vacuum to create the power assist for the brakes. When you press down on the brake, air at atmospheric pressure is allowed to one side of the diaphram. The difference in air pressure multiplies the force on the pedal by about a factor of four.

It takes vacuum with no leaks for the system to work right. If the diaphram has a leak in it, or if there is a leak in a vacuum line or a check valve which is in the line, you may hear hissing, and the power assist will be less, or non-existent.
 
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