hard brake pedal with engine off no pedal when started replaced all brakes rear clyinders and master cylinder no air in lines
hard pedal when not running pedal go's to floor when started, replaced all brakes rear wheel cylinders and master cylinder bleed brakes no air in lines ?
My car has 15000 miles.
My car has a manual transmission.
Experienced mechanics share their insights in answering this question :
From the description provided, my first step would be double checking the connections at the master cylinder as well as double check the flexible brake lines at each wheel. A small leak can duplicate the brake pedal falling to the floor. If you are 100% certain there is no air in the system, it is very possible that your F-250 may have a faulty brake master cylinder.
The brake system on the your 1987 Ford is pretty basic and if there are no leaks, then it is VERY likely the master cylinder is the problem. If you are performing the work yourself, you may want to try exchanging your brake master cylinder for a new one.
Be sure to properly bench bleed your brake master cylinder before installing it on to the brake booster as well. I would then bleed the entire brake system at each wheel just to be sure there is absolutely no air in the system.
Of course if you did not perform the work yourself, or if you feel like you’re stuck, then I would recommend enlisting the assistance of a certified technician. They will be able to quickly determine the reason for your brake pedal falling to the floor.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
Check the Brake Booster A bad power brake booster is a common cause of a hard brake pedal. As such, it should be your first consideration when diagnosing a hard brake pedal. Here`s how to manually check if your brake booster is problematic: Press and release the brake pedal consecutively while the engine is off.
A worn or malfunctioning master cylinder. If the master cylinder isn`t performing as designed, it may need to be replaced. Defective replacement cylinder. If, after the master cylinder has been replaced and the system has been bled, and still your brake pedal goes to the floor, the new master cylinder may be defective.
If the booster isn`t of the proper size, proper assist can`t be provided and the pedal will become hard due to the fact that the system is tapped out. At this point, the pedal becomes hard as the booster has done all it can but the vehicle still needs more.
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.
A brake pedal that is stiff and won`t depress can be caused by several different things, including air in the hydraulic system, a leak in the hydraulic system, or simply dirt and grime on the pedal. Your car won`t start due to a faulty battery, fuel pump, starter motor, or ignition switch.
A faulty brake master cylinder can also cause a hard brake pedal. The brake master cylinder is responsible for converting the force from the brake pedal into hydraulic pressure that is transmitted to the brake calipers.
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.
First, with the engine turned off, pump the brake pedal several times. The pedal should feel slightly spongy for the first few applications, then gradually get harder as the vacuum stored in the power booster is exhausted.
It doesn`t harm the vehicle.
There is a common myth that engine braking is harmful to your car and a bad practice. However, engine braking won`t damage your car as long as you follow safe, sensible driving practices.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
hard brake pedal with engine off no pedal when started replaced all brakes rear clyinders and master cylinder no air in lines
ANSWER : From the description provided, my first step would be double checking the connections at the master cylinder as well as double check the flexible brake lines at each wheel. A small leak can duplicate the brake pedal falling to the floor. If you are 100% certain there is no air in the system, it is very possible that your F-250 may have a faulty brake master cylinder.
The brake system on the your 1987 Ford is pretty basic and if there are no leaks, then it is VERY likely the master cylinder is the problem. If you are performing the work yourself, you may want to try exchanging your brake master cylinder for a new one.
Be sure to properly bench bleed your brake master cylinder before installing it on to the brake booster as well. I would then bleed the entire brake system at each wheel just to be sure there is absolutely no air in the system.
Of course if you did not perform the work yourself, or if you feel like you’re stuck, then I would recommend enlisting the assistance of a certified technician. They will be able to quickly determine the reason for your brake pedal falling 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.
Changed brake master cylinder, bled 10 times, and the pedal is soft The rear brakes are not locked but close. Truck now running rough.
ANSWER : You will have to bleed the brakes from the farthest location all the way to the master cylinder. There is still air in the lines causing the issue. Check the vibrations on the vehicle to see if the engine mounts are damaged or if the brakes are not releasing causing the engine to run harder than normal to overcome the braking force. If you need further assistance with your vehicle’s brake system, then seek out a professional, such as one from Your Mechanic, to help you.
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.
Soft brake pedal after replacing rear brakes and master cylinder 2003 Audi A4
ANSWER : Hello. If you have no pressure to the rear calipers at all and if the master cylinder is new then you may have forces some debris into the ABS unit when you compressed the pistons in the rear calipers. In some cases the system can be pressure bled to fix it but it may need a new ABS unit.
I just replaced my brake master cylinder and the brakes still feel soft. What do I need to do after I replace the master cylinder
ANSWER : From what you’ve described you will have to bleed your brakes. Also, I believe you may have a leak in one of the lines. You may want to use a wrench and tighten the lines a little more. If you’re unable to fix this yourself, consider YourMechanic, as one of our mobile technicians can come to your home to bleed your brakes, diagnose the Check Engine Light, and help you make the appropriate repairs to your car.
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.
Rear brakes not grabbing – 1995 GMC K2500
ANSWER : Hello. It is not in the ABS, but may be the proportional valve not giving the correct pressure split front to the rear. The vehicle never had enough pressure for the rear brakes. Have the rear shoes adjusted properly if you have drum brakes. You should check to see if there is an updated part to replace the old one. If you would like to have this done, a certified technician from YourMechanic can inspect the brake system and let you know what repairs are needed.
