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: Q: Brake light won't go off

Hello! The brake light staying on can stem from something as simple as low brake fluid. However, on your particular vehicle the brake light will commonly come on due to a fault in the ABS system controller module. The module...

Q: I have a 2000 Subaru Legacy. When the car is parked or foot is on the break the idle goes up and down. Doesn’t stall out though.

This problem of erratic idle speed is often referred to as "surging" or "hunting". The causes include a faulty idle air control valve or circuit (IAC), a faulty ECM (not common), faults in the fuel pump control circuit, defective spark...

Q: my car is an hyundia and it was running the other day I woke up to go to work and it wouldn't crank, the fuel pump works and I do

If the starter motor is not even cranking the engine, among the first possibilities is a weak battery, excessive voltage drop in the starter circuit due to poor electrical connections, or a dead starter/solenoid. Prior to performing diagnostics the battery...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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.