Why is my brake pedal going all the way down to the floor?
When I start braking everything seems normal, but the more pressure I put on the pedal the farther down the pedal goes, at one point it will just drop to the floor. My brake light came on, and I checked the fluid and I was low. So I added more brake fluid, the light went off but the pedal continued to hit the floor. Why is it doing that? I know generally that brake pedals shouldn't hit the floor, and it seems when I pump the brakes it's ok for a few seconds, then the pedal just drops.
My car has 101900 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
If you are having to refill the brake fluid from it getting low and the brakes go to the floor means you have a leak in the brake system somewhere. You may have a broken brake line, leaking wheel cylinder or caliper. You should not drive the vehicle until the brake system is inspected and repaired from the leak.
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When brakes are not as responsive as what they should be, or if the brake pedal “sinks” down to the floor, this is a possible indication of a braking system leak. It could be a brake fluid leak, or a brake hose air leak.
A pedal that stops hard at the bottom but has excess play at the top is usually the result of a master cylinder or pushrod issue. A pedal that`s spongy or mushy can be caused by air intrusion, contaminated brake fluid or a mechanical component moving beyond its designed range of motion.
The classic symptom of a failing master cylinder is a brake pedal that “dives” or sinks slowly to the floor while pedal pressure is being applied. Another sign to look out for is any leaks around the master cylinder. If a seal is worn out, it may leak past the seal and onto the pushrod that attaches to the brake pedal.
Usually, your brake pedal will sink if the ABS or master cylinder cannot maintain the proper hydraulic pressure. This inability to maintain hydraulic pressure will not only make your brake pedal sink to the floor, but it will also make it much more difficult to stop your automobile.
EXCESSIVE PEDAL TRAVEL
Possible causes include worn brake linings, misadjusted drum brakes, and air in the brake lines. Potentially dangerous because the system may run out of pedal before the vehicle can be safely stopped.
Use a screwdriver to press and hold the plunger in the rear of the master cylinder. The plunger should be very firm, if not immovable, past a few millimeters. If the plunger keeps moving in, this indicates a fault of at least one of the internal seals.
The ABS modulator is the hydraulic assembly in vehicles that use the anti-lock braking system (ABS) to optimize the brake pressure. A damaged modulator may lead to malfunctioning of the brake valve resulting in spongy brakes.
If air gets into the brake lines, it can prevent brake fluid from flowing properly, causing the brake pedal to feel spongy or soft. If the brakes are soft or spongy, this is a good time to change or flush the brake fluid. Flushing the brake fluid, commonly called bleeding the brakes, gets rid of the air.
A malfunctioning Anti-lock Braking System (ABS) can also cause a hard brake pedal. The ABS system is responsible for preventing the wheels from locking up during emergency braking. If the ABS system malfunctions, it may cause a loss of hydraulic pressure, resulting in a hard brake pedal.
Vacuum – or really lack of vacuum pressure – is the most common cause of a hard brake pedal, and therefore the first thing to look at when a hard pedal is present. Any brake booster (whether from Master Power or any other supplier) needs a vacuum source to operate.
Brake pulsation usually only has one cause, which is warped rotors/brake discs.
ABS sensors are cylindrical magnets surrounded by a coil, and mounted inside the disc brake support. They are subject to collect metallic debris from the pads, which will degrade the generated signals to the ABS computer, causing it to actuate ABS inappropiately, evident by the brake pedal pulsating.
The more you focus on timely rotor cleaning, brake fixes and replacements, the less likely you will run into this problem. Pulsating or surging brakes is a sign that ultimately occurs as a drastic byproduct of friction. This friction is caused due to two metallic components rubbing against each other.
By far the most common problem with hydraulic braking systems is when the system is low on brake fluid. As the system is designed to function as a closed system, it requires a consistent amount of brake fluid in the system to function correctly.
Brake pedal difficult to push – The most common sign of a brake booster leak is your brake pedal feeling “harder” than normal. It will require more force to work and increase your stopping distance. If you notice this, you should get your car inspected as soon as possible. This is because it can affect your safety.
Brake Booster Check
With the car turned off, pump the brake pedal four or five times until you get a hard brake pedal. Continue to hold the brake pedal down with moderate pressure and start the vehicle. The brake pedal should drop.
If your foot slowly sinks to the floor with normal pressure on the brake pedal, the master cylinder is leaking internally. To diagnose a clutch master, clamp the rubber fluid line near the slave and press the clutch pedal. If the master cylinder is good, the pedal won`t move.
Yes master cylinders can fail without leakage, the clutch master cylinder has a piston inside and there are separate channels for hi-pressure line and return(low pressure) line and their location in the cylinder differs for manufacturers.
The Three Most Common Reasons for a Soft Brake Pedal
There is a leak in the system someplace other than the brake master cylinder. One or more of the calipers has a frozen or rusted moving part that isn`t moving as designed.
The most common reason for a soft brake pedal is simply air still in the system. The easiest way to diagnose this problem is to pump the brake pedal gently a few times. In doing so, the pedal should become firmer with each gentle press of the pedal.
No. If your brake pedal feels spongy, your vehicle is not safe to drive. Identify and repair the underlying issue as quickly as possible. Spongy brakes are common and dangerous problems for any vehicle and indicative of a deeper problem.
Then it could be that old brake fluid is causing the poor brake performance. Or, you could have a possible leak causing your fluid to be low. Either way, get it checked out! This is one of the most common causes of spongy brakes.
The following are some of the factors that affect braking distance: speed of the vehicle, road conditions, tire condition, weight of the vehicle, and the efficiency of the braking system.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Supportive bar attached to brake pedal interrupts proper braking process
ANSWER : It’s possible to have someone alter the brake pedal or adapt a brake pedal from a different vehicle. You may call around to some customization shops to see if anyone is interested in taking on the project. But first, I would try reaching out to the selling dealer with your concern – especially since it is a new model. Good luck.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
Why is my brake pedal going all the way down to the floor?
ANSWER : If you are having to refill the brake fluid from it getting low and the brakes go to the floor means you have a leak in the brake system somewhere. You may have a broken brake line, leaking wheel cylinder or caliper. You should not drive the vehicle until the brake system is inspected and repaired from the leak.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
Low brake pedal and anti-lock brakes are not kicking in.
ANSWER : The brake pedal is working to stop the vehicle, but there may be air in the controller unit causing the ABS brakes to not function. I recommend bleeding the brake system from the farthest location from the master cylinder to the master cylinder including the ABS unit. If the brakes are still spongy after a full bleed, then the controller will need to be replaced. If you need further assistance with your brake pedal being spongy, then seek out a professional, such as one from Your Mechanic, to help you.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
Brake pedal goes 3/4 way to floor
ANSWER : Hello there. This is a more unusual problem, especially given the amount of parts you have replaced. In most cases, the pedal travel is due to either the master cylinder or the brake booster, sometimes both.
Given that these have been replaced, there may be other causes. The most likely fault that comes to mind would be that there may be air in the brake fluid system or one of the brake calipers could be stuck requiring extra travel to engage.
This can occur over time and brake fluid attracts moisture or from replacing the brake components. Some vehicles may be difficult to remove all of the air from when bleeding and require the vehicle to be bleed different ways. If the brake system was vacuum bled then it may need a mechanical bleeding to resolve the issue. If you would like to have this done, a certified mechanic can diagnose your brake pedal issue and determine what should be done next.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
Brake sensor is to sensitive causing brakes to flicker while driving. 2005 Mercury Montego
ANSWER : Hi there – your brake light switch needs a minor adjustment. It is adjusted too "tight" or close to the brake pedal lever, or possibly has failed. Adjusting/replacing it will eliminate this flickering problem. I recommend a brake light isn’t working 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.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
abs light on brake line broke have been replace I bleed brake line but brake pad still go to the floor now wheels lock up
ANSWER : Hello. If the brake pedal is going to the floor then that means that it is not building pressure. If the brake system has been fully bled and there is no air in it then most of the time it is a bad master cylinder or it can be caused by a bad ABS module. If the brake fluid was low and if air got into the system then the only way to properly bleed it is with a scan tool that would allow you to open and close the valves in the ABS unit. Air gets trapped in these easily if the brake fluid gets low. This can also explain why the brakes are locking up. I would usually use my scan tool to bleed the system out first before going any further. I would also scan the brake control module to see what it is reading as a fault. If there is no air in the system and if there is no prominent code then I would replace the master cylinder first. If you want to check out why your brakes are locking up, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
Hard brake pedal and rear brakes locking up.
ANSWER : Hi. I will help you with this issue you are having with your 2001 Durango. Unless you bled the master cylinder, it is possible there is still air in the system. If you car is equipped with ABS, air could have also gotten trapped in the ABS modulator. If ABS equipped, a bi-directional scan tool would be essential to manually activate the ABS system to clear air from that segment of the lines while you are bleeding the system. It is also possible that in all of this work somehow the proportioning valve has been affected causing the desired pressure differential, front versus back, to get out of spec. Using a 2,500 PSI gauge, you can check the pressures at each wheel and that will definitely give you a clue as to which brake circuit is the issue (or both), whether the proportioning valve is working properly and whether the line pressures at each wheel are within spec. Should you need a second opinion, by all means feel free to contact YourMechanic for assistance and we will diagnose and repair the issue for you.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
Brake pedal going all the way to the floor
ANSWER : From the symptoms described, it leads me to believe that your Mitsubishi is experiencing concerns with the master cylinder. A failing master cylinder can duplicate the problems you are experiencing, such as brake pedal going down to the floor. To be 100% certain, i recommend enlisting the assistance of a certified mechanic to inspect the brake system of your Mitsubishi as soon as possible. They will have the experience and tools needed to determine exactly why your Diamante is experiencing this concern with the brakes and assist in making the necessary repairs to ensure your brakes work, especially when you need them most.
Read Full Q/A … : Why is my brake pedal going all the way down to the floor?
