Q: My breaks sometimes stop car completely and sometimes it doesn't what would cause this?

asked by on

When driving my breaks sometimes work great other times when I push my break peddle down the car slowly breaks but not completely where it takes longer for the car to break compleatly. The system has been bled and new calipers and break pads. I'm thinking the master cylinder but I see no leaks and have fluid in reservoir.. what's the issue?
My car has an automatic transmission.

Usually a person describes such an experience as more force than usual is needed to stop the car. I am not exactly sure what you are experiencing here, so I will address a few things. Speed and weight of your vehicle will make braking less effective. All things being equal, if you are coming to a stop at the exact same speed and the exact same distance, your master cylinder could certainly be the issue. So could your anti-lock brake system. Your master cylinder can have internal leaks that will affect its ability to create enough pressure at your wheels. Your anti-lock breaks have the ability to do the same thing, but in much different ways.

It sounds as if someone has done a lot of work to your car already without experiencing your issue. This suggests you have an intermittent problem. Intermittent problems are inherently difficult to catch. In order to catch your problem, you will need to leave your car with someone for several days so they car do the best they can to recreate the problem. If stopping is still safe, I would recommend waiting until the problem becomes worse and is much easier to identify.

Usually if it is a anti-lock brake problem, there will be a anti-lock brake light on or the brake pedal will bounce when braking.

I recommend having a certified technician, like one from YourMechanic, diagnose your brake system firsthand to help you figure this out.

Good luck!

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. My breaks sometimes stop car completely and sometimes it doesn't what would cause this?

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: I have 2009 Toyota Highlander, LIMITED.

Since you recently did some work on the driveshaft, I would first suspect there was a problem as a result of the installation process. Before you begin taking the wheel off for inspection, I would connect a scanner to retrieve...

Q: My car starts idol fine runs for four seconds maybe six seconds then shuts off

Hello. There are a few problems that can cause this. If there is the correct fuel pressure and if there is compression, then the sensors need to be checked with a scan tool to see if any of them are...

Q: Q: Car vibrates when stopping.

Your problem is a common one. The vibration/pulsation you feel when braking is possibly due to warped rotors. Rotors are a smooth machined metal surface that your brake pads make contact with when you apply your brakes. When the rotor...

Related articles

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...
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.