Skip the auto shop - Our mechanics make house calls

Q: Hissing noise when brake pedal depressed.

asked by on

Hissing sound when brake pedal is depressed. Fluid reservoir is full and there is no wetness inside under or near the pedal or carpet (I've even pulled the carpet up to look) so it doesn't look like I'm leaking fluid into the booster. The pedal is not hard to depress, and there's no smell or anything else. Just the hissing sound.

My car has 200000 miles.
My car has an automatic transmission.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Floor mat entrapped accelerator, increasing speed, and destroyed engine

Hello. I have seen this occur several times on this particular model. Due to the design of the floor mat it comes loose and gets under the gas pedal which causes this to occur. This happens even more often with...

Q: Problem with not dying

Hello there, thank you for asking about your 1994 GMC Jimmy. The engine would need to be checked for a stuck open EGR valve or a major vacuum leak. The most common cause is the EGR stuck open with carbon...

Q: transmission speed sensor

What you're describing seems more like a problem with the speedometer cable and housing. The cable that attaches to the sensor and then to the speedometer in the dash has multiple opportunities to become damaged. The first thing I'd do...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.