Brake system malfunction
My car has gone around 160,000 miles. Lately, the braking system started malfunctioning. Brake pedal is kind of spongy when I press it. Ocassionally, even though I floor the brake pedal, it doesn't work. Also, I've noticed dragging and smoking of the left front caliper. So, the brakes sometimes fail completely while other times work very poorly. I've checked for leaks and there are none. The fluids look fine and are at proper levels. What might be causing this? What repairs should I do?
Experienced mechanics share their insights in answering this question :
The master cylinder is likely worn out and should be replaced. The rubber cups simply allow the brake fluid to slip past, rather than compress, when the brake pedal is pressed. I would also replace all of your brake hoses – front and rear. They may look fine externally, but have internal weakness that are contributing to the behavior you describe. They are 22 years old after all! A YourMechanic professional can help with both of these repairs.
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Anti-lock braking systems (ABS) help you steer in emergencies by restoring traction to your tires. What It Does: Helps prevent wheels from locking up – possibly allowing the driver to steer to safety. What It Does Not Do: May not shorten stopping distance; pedal may vibrate or push back – that`s normal.
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.
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.
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.
WHAT IS ABS? ABS stands for Anti-lock Braking System, a key safety feature in most modern cars and trucks. Anti-lock brakes work with a car`s regular brake system by automatically pumping them in the event of a sudden stop.
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.
Does A Faulty ABS Module Drain My Battery? An ABS module failure can cause the ABS pump to run continuously. This can eventually drain out your vehicle battery. To prevent a flat battery or burning out the ABS pump, have your mechanic remove the ABS fuse.
The ABS module will need to be programmed once everything is installed. This procedure also will vary quite a bit depending on the manufacturer. Tip: For this step in the ABS module replacement procedure, refer to the manufacturer`s instructions to find the specific programming procedure.
When your ABS system malfunctions are can also cause a spongy brake pedal. Your ABS system is designed to allow the driver to maintain more control of the car in a high-speed stop.
The anti-lock function will stop working properly, which may increase the distance it takes to safely stop your vehicle. The rear tires will lock, which will increase vehicle swing on turns and may make your vehicle more difficult to control.
Resetting Your ABS Dashboard Warning Light
Step One: Disconnect the positive cable from your car battery. Then, hold down the brake pedal to drain the vehicle`s electrical system. This will result in a reset of the car`s central computer. Plug the cable back in to restore power.
If you need to, use warm, soapy water to scrub away dirt from the sensor—just make sure that the sensor dries completely before you replace it. Use a wire brush or file to gently grind away stubborn rust or dirt. Be careful if you do choose to do this, as excessive cleaning could damage the sensor.
When the driver brakes sharply, ABS works by sensing when the wheels are about to lock. It then rapidly reduces and increases the braking pressure multiple times per second, applying the optimum pressure. This allows the wheels to keep moving as the car slows down, instead of locking up.
When the speed sensor detects that a wheel has locked, the hydraulic valve automatically releases brake fluid pressure, thereby releasing the braking pressure. When rotation of the wheel is detected, the pump engages to create pressure and the braking system reapplies the brakes.
“An anti-lock braking system (ABS) prevents wheels from locking up and cars from skidding when the brake is harshly applied, especially on slippery road conditions, guaranteeing safer driving.”
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
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 … : Brake system malfunction
EPC light on 2004 Jetta. Code said brake switch faulty, but brakes lights worked. Replaced brake switch, now no brake lights.
ANSWER : Hi there. The first thing that pops in my mind beyond of what you have listed is perhaps the electrical harness attached to the brake switch. Perhaps the harness itself is damaged or you have an exposed wire, loose ground wire somewhere. You might want to have a professional mobile mechanic come to your location and complete a brake lights not working inspection to help you diagnose this issue.
Read Full Q/A … : Brake system malfunction
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 … : Brake system malfunction
When I put my foot on the brake my back left brake light goes off, when I take it off the brake the brake light comes on
ANSWER : I would suggest trying to disconnect and reconnect the wiring to the rear lights. I have seen these older Toyota vehicles rear lighting short out on the lights themselves due to the way the light circuit was made on the lamp housing. Look at the housing circuit on the light to see if one is touching another, and that could tell you why it is malfunctioning. There could also be a problem with the brake light switch. If you are not comfortable dealing with wires, I recommend getting in touch with a certified mechanic who can look at your brake light issue for you to see what’s going on.
Read Full Q/A … : Brake system malfunction
check break system and indicators of side brake, doors open,and traction system and full light warning in dash board
ANSWER : Hi there, thanks for writing in.
It sounds like you are having a serious electrical malfunction, which is very hard to diagnose without being able to look at the car first hand. The first step to diagnosing your electrical issue would be to scan all the relevant control modules in the vehicle, to see if there are any faults relating to any of these issues. It sounds like somebody at the dealer has been trying to fix this problem, so it may be a more involved one. I have personally seen failed control modules cause things like this, but that is no guarantee that it’s the problem in your case. It would be best to have a qualified independent technician, such as one from YourMechanic, look at your car to diagnose your electrical problem.
Read Full Q/A … : Brake system malfunction
I replaced the brake light switch. Gear lever unlocked because it had locked. Now the brakes feel hard.
ANSWER : Hi, thanks for writing in. You need to check the brake switch install adjustment. You may have the switch adjusted too tight and it is holding the the brake pedal partly down. This will cause the brake master cylinder to not release the brakes when you let off the pedal. Readjust the switch away from the pedal until you feel some free play again in the pedal. This should fix the problem. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.
Read Full Q/A … : Brake system malfunction
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 … : Brake system malfunction
Driver has to pump brake pedal multiple times to brake
ANSWER : I’m not familiar with a pump assisting the system, but the master cylinder creates the hydraulic pressure needed to transfer power from your floor to the brake assemblies. A failing master cylinder can feel like a leak in the hydraulic system as it cannot create the proper pressure. Have a certified technician, like one from YourMechanic, physically inspect the brake system for any actual leaks as well.
Read Full Q/A … : Brake system malfunction
