My breaks sometimes stop car completely and sometimes it doesn’t what would cause this?
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.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
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!
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
The most common ABS problems occur when sensors become contaminated with debris or metal shavings. Malfunctions also occur when sensor wiring becomes damaged, resulting in intermittent or no continuity.
Faulty ABS systems can behave erratically, pumping your brakes even under normal driving conditions, and producing strange clicking noises, even when the brakes aren`t engaged. If you notice any of these random clicking sounds or lock-ups, it`s quite possible that your ABS module needs to be replaced.
If the ABS system is not functioning properly, then your vehicle is likely to skid, hydroplane and lose traction under heavy braking conditions. The last time you want to find this out is when you need it most in tough conditions, which could lead to an accident on the road.
Pump your brakes or take your foot off the brake pedal, because that will release the anti-lock system. ONLY pump your brake if the ABS fails and your vehicle starts to skid. Drive aggressively.
The four common reasons that typically cause this light to turn on include a malfunctioning ABS module, low levels in the fluid reservoir, broken wheel speed sensors, or the system is turned off. Your ABS actually shares some important components with another system in your vehicle: your traction control system.
In certain cases, depending on the model of vehicle, when the ABS module fails, the brake pedal may become unresponsive. This is an obvious problem, as an unresponsive brake pedal will not stop a vehicle, or will not be able to do so in an adequately safe manner. In most cases, this will happen slowly, over time.
If your ABS light comes on individually, you are safe to drive your car to your destination, as your normal brakes will still work. You will, of course, have to be more careful as your ABS will not respond in case of an emergency.
It`s very dangerous to be out on the road when you know your ABS system isn`t working, regardless of the reason. If you cause a crash and knew about the faulty sensor, you could have greater liability for the damage.
Without ABS, a rapid, hard brake application could cause wheel lockup and loss of vehicle steering control, if the driver does not pump the brakes correctly or limit the brake pedal force to prevent wheel lockup. Therefore, more driver skill is needed to obtain short stops without ABS.”
If your brakes go out, you want to do three things. First, downshift to a lower gear. Second, if you have regular brakes pump the brake pedal fast and hard to build up brake fluid pressure. If the brakes haven`t started working after three or four pumps go on the step three which is use the parking brake.
You can still drive without a functional ABS control module, as long as there`s no problem with your conventional brake system. However, take extra care, especially in wet or slick conditions, as the brakes` anti-lock element won`t work, and you likely won`t have steering control if your tires lock up.
Removing a wheel speed sensor will disable ABS—and sometimes, stability control. If your car has a yaw sensor, you can unplug that for results. You can also try simply unplugging the ABS module, though that could adversely affect your car`s braking performance.
In certain cases, depending on the model of vehicle, when the ABS module fails, the brake pedal may become unresponsive. This is an obvious problem, as an unresponsive brake pedal will not stop a vehicle, or will not be able to do so in an adequately safe manner. In most cases, this will happen slowly, over time.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
My breaks sometimes stop car completely and sometimes it doesn’t what would cause this?
ANSWER : 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!
When I try to stop I either have to pump my breaks to stop or my wheels lock and stop my car and I am going threw brake fluid
ANSWER : Hello. I would start by checking the brakes. A loss of fluid indicates a fluid leak. Most of the time this comes from either one of the calipers or wheel cylinders. It may also be the master cylinder from the description you are giving. The only way to know for sure what is going on is by inspecting the brakes. If you want to have this done, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose this and provide you with a brake fluid service if necessary.
When I drive it and come to a stop with my foot on the brake my car revs up and sometimes shuts off and I have to start up again 2006 Chevrolet Impala
ANSWER : Hi – first task is to read any problem codes, whether the Check Engine light is on or not. Most auto parts stores will do this for you for free on a "time-available" basis. Any codes extracted are useful for diagnostic purposes. Based on your symptoms, the throttle position sensor is a leading failure possibility. A malfunctioning idle air controller could also cause the unpredictable idling issues, but not a shut-off while driving. I recommend a car stalling inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
My car doesn’t respond to the gas pedal like it should
ANSWER : Hello, thank you for writing in. The engine is likely sensing an issue and compensating for it. When you restart the vehicle, the component may be passing its start up tests, and the engine stops trying to outperform itself. Start by having the vehicle scanned for diagnostic codes. If there is another sensor to blame, it may show up there and make diagnostics a lot easier. If not codes come up, you will want to test the fuel pressure available at the engine, and make sure the fuel system is working properly. You can also clean the throttle and test the throttle position sensor. For more help with diagnosing and resolving the issue, contact our service department to schedule an appointment.
What’s wrong with my car?
ANSWER : This may actually be a faulty throttle position sensor. The throttle position sensor is used to monitor the throttle position of the throttle plate inside the throttle body in relation to your foot position on the gas pedal. Based upon the inputs from the sensor reading your foot’s position on the pedal, the ECU then makes the direction to supply more or less fuel to the motor. When this sensor is not working properly, this can cause intermittent responses when pressing the gas pedal. I would suggest having a professional from Your Mechanic come to you home to diagnose your throttle control system.
When I stop at the stop light or a stop sign my car shuts off.
ANSWER : It sounds like you may have a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
I was stopped on the freeway, started to go about 5 mph, the car jerked and stop without warning like the wheels locked up.
ANSWER : Hi, thanks for writing in. I’d be happy to try to help. It is hard to definitively diagnose what the issue is. At first it seems like a transmission issue. Automatic transmissions are rather complicated and can do strange things when they malfunction. If not an issue with the transmission, you could also have a clutch issue. Always start by checking the simple components first. Check your transmission fluid level. Make sure your transmission filter is clean and debris free. When you have the transmission pan off, you can look and see if there are any metal shavings at the bottom. There is often a small magnet at the bottom of the pan designed to gather any metal shavings for a quick diagnosis. This is a sign of more serious transmission problems. Unless you have experience with automatic transmissions, it is not recommended that major repairs be done at home. I suggest taking your car to a transmission specialist for help.
Car shifts hard and rpms rev high on there own or car doesn’t shift at all, ABS and traction control lights are on also. 2005 Chevrolet Cobalt
ANSWER : Hi there – first task is to be sure the transmission fluid is at the proper level, and in good condition (more pink than black, and no burned smell). Low fluid, or dirty fluid, can cause lots of unexpected transmission behavior. The second task is to check for problem codes, whether the Check Engine light is illuminated or not. The possible problem we’re looking for here is a failing throttle position sensor – which interacts with the transmission controller and affects shifting behavior. I recommend a transmission inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
