Skip the auto shop - Our mechanics make house calls

Q: Brake pedals not firm halfway down

asked by on

My car's brakes have been fine until now. Recently, however, the brakes seem to "fade", or not have as much pressure when the brake pedal is halfway down. It will then firm up again. This happens when I'm driving. If the car is shut off, the pedal pump has plenty of pressure and stays firmly up. I guess that means the hydraulic part of it is fine.

I thought maybe the vacuum assist was the problem, since the problem only happens when vacuum is applied. I replaced the power assist, but the problem remains. The only other thing I can think of would be the master cylinder, but the pedal is fine when the engine is off. Why are my brakes or brake pedal less firm while driving?

A: Lack of brake power assist would typically ...

Lack of brake power assist would typically result in a hard brake pedal, not one that sinks to the floor. My guess is that the master cylinder is faulty. A bad master cylinder will often result in a pedal that sinks to the floor.

Whatever the cause, this is a potentially dangerous situation that should be inspected firsthand by a professional. I suggest you contact the team at YourMechanic to inspect your uneven brake pressure since we make house calls.

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・Save up to 30%

Get a quote

What others are asking

Q: The radio will not respond or turn on, opens up on LCD then immediately crashes, other buttons do not work.

Hello, thanks for writing in about your Ford Focus. From what you've described, the radio control head would need to be scanned with a factory level scanner to see if the unit needs to be sent out for repairs or...

Q: Noise coming from tires

Hi there. Diagnosing this issue would require a mechanic to take your vehicle on a test drive and determining what noise is coming from your vehicle. This issue maybe related to your tires being out of balance. A qualified mechanic...

Q: Radiator leak

Hello, if you have a coolant leak from your radiator, then this is something that need to diagnosed and repaired sooner than later to avoid further engine damage. If it's a small leak, and your best guess is the radiator,...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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.