Skip the auto shop - Our mechanics make house calls

Q: My brakes hiss back at me

asked by on

When i step on my brakes there stiff and hiss back at me they work still but not like they use to. I wanted to know if its my booster or my master cylinder, Ive also bleeded my brakes 2 times with no difference instead a bit stiffer than before. The first time they were VERY soft they almost didnt work. Now When it hisses it sounds like the dash but when you get out i cant determind if its the booster or master cylinder. Thank You.

My car has 258006 miles. I rebuilt my engine at 242,000 miles. My car has an automatic transmission.

That hiss you hear is a vacuum leak. That leads to the hard brake pedal. Power brakes rely on vacuum to make braking easier. The vacuum leak has reduced vacuum within the brake booster and is making the brake pedal hard - similar to older cars without power brakes basically. It may also be effecting your engine performance and economy. The leak can be the brake booster housing itself, or the vacuum connection to it. Have a certified technician look into the hard brake pedal as soon as possible.

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: What is price for water pump and timing belt change for 2001 Passat V6 and how long does it take

Hi there. If you see coolant (green, red, or yellow fluid) underneath your car, it's a good idea to have the cooling system inspected for additional leaks before replacing the water pump. In order to give you an accurate quote...

Q: Fix vacuum leak and reset idle.

The idle should not be adjusted unless it has been tampered with. The idle is controlled by the idle air control valve. The vacuum leak once identified and fixed should correct any idle problems you have.

Q: Traction Control System

As you know, the VSC light relates to the vehicle stability control system otherwise known as the traction control system. The traction control system monitors the steering stability of the vehicle and engages when loss of traction has been detected....

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.