Skip the auto shop - Our mechanics make house calls

Q: Brakes hiss when I use them

asked by on

The ABS light has been on for a few weeks in my 2007 Camry V6 that I have driven for around 104,000 miles, and there's a hissing sound when I apply the brakes. I had my brakes and rotors changed last week by my mechanic friend, and I still was having the same issues. Today, the brakes lost power and it's like having old school manual brakes. Help, please.

Well, it sounds like you may have a vacuum leak coming from the brake booster. I definitely recommend you do not drive the vehicle until you have an independent mechanic look over it, as this is a major safety concern. Typically when you will hear a hissing sound from applying the brakes, or if you hear the sound but the hissing noise goes away when the brakes are applied, it is a very good indication that the diaphragm in the brake booster is failing. The diaphragm allows air to escape the system and thus makes it harder to apply the brake pedal when it is failing. In addition to this, a bad or failing brake booster can be a symptom of another hidden problem, which is known as a leaking master cylinder. Now these two issues don’t always go hand in hand, but they often can and a certified technician will be able to determine if the master cylinder is leaking by separating the master cylinder from the vacuum brake booster and inspecting the cavity in the vacuum brake booster for signs of brake fluid. Brake fluid can eat away at and break down the diaphragm inside the vacuum brake booster as well. Before a repair is attempted, a diagnostic scanner is used to communicate with the ABS computer to determine if the warning light is related to this primary concern. If it is the case, the diagnostic scanner is used to clear the code from the computer and you can have the power brake booster is replaced. If that is not the case, further diagnoses will be needed to identify the problem.

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: Car does not start

Hi! First, we will need to determine which no-start situation has occurred. If you turn the key and nothing happens, there is a fault in the starting/charging system. An engine that turns over but will not start, often has issues...

Q: break pads and rotor needs to be changed

Hi there. You can get an estimate for brake pad and rotor service for your 2007 Hoonda Civic by clicking this link. Once you are in contact with the sales team here at YourMechanic.com, let them know what parts you...

Q: Brakes not working

I would first look at the fluid level in the master cylinder. If the fluid level is low, there is a possibility that a brake line was damaged and now leaks, perhaps related to the car being towed. If the...

Related articles

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
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.