Quote:
Originally Posted by Matthew_H
So I recently noticed a hissing sound while I was driving. High pitched, almost inaudible inside the car while the engine is running. As it turns out, it's appears to be coming from the brake booster in the engine compartment. After it charges, you can hear a quite noticeable hiss that decreases in intensity until the the boost charges again.
The way I understand it, the brake booster should engage when the ignition turns on, and then again with every other press of the brake pedal (or whenever the boost needs a recharge). Mine activates with the key, takes several seconds to charge, and then re-engages after only being off for a few seconds. And it always engages with each press of the pedal.
I have an audio file of the behavior with the engine off and no pedal presses, but I don't know the best or preferred method of uploading it (either here or some other site). I'll look into that. In the mean time, any thoughts or suggestions?
Edit: I should note that aside from the booster running a lot and the hissing sound, the brakes work and I've never had a problem stopping.
|
More than likely it's the accumulator that going bad or at the very least the accumulator O-ring is bad.
The little electric ABS/booster motor runs the ABS/booster pump, the pump builds up pressure in the accumulator that pressure assists the master cylinder when braking and also is the pressure used when the ABS is activated.
