Skip the auto shop - Our mechanics make house calls

Q: Brake sinks slowly into the floor and have no leaks on master cylinder

asked by on

So when i drive the brake slowly goes down to the floor to the point were im still rolling and the brake doesnt go any further. but when i pump the brake i slowly regain pressure and i have checked all around the master cylinder and there have been no leaks.

My car has 125274 miles.
My car has an automatic transmission.

A: Hello. The master cylinder does not have to...

Hello. The master cylinder does not have to be leaking externally for it to be bad. The pedal sinking to the floor then coming back somewhat when you pump it is generally a tell tale sign that the master cylinder is bad. Have a local expert verify the problem with the brake system and replace the master cylinder if necessary.

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: After belt replacement, belt tensioner squeaks and is loose

More likely mileage and time wore the tensioner out. The tensioner bearing wears out with mileage - it's good to replace the tensioner pulley/bearing when replacing the belt. The tensioner itself is spring-actuated, and the spring can get weak over...

Q: Bad gas mileage, engine misfire - 1992 Cadillac Allante

There can be multiple causes, but it sounds like your fuel injection is injecting too much fuel into the engine for the amount of air it's using. Faulty temperature, air flow, or oxygen sensors, a dirty throttle body or incorrect...

Q: Front tire leaning.

When the top of the tire leans in more than normal this is usually caused by some sort of failure in either the upper ball joint upper control arm or control arm bushings. Sometimes nothing has failed at all, upper...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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 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...