Breaks randomly fail?

My breaks failed this morning and I almost go hit! I parked the car after it finally came to a stop and let it sit with the heater on for a few and when I was calm enough, I drove it around a neighborhood to test the breaks. It worked fine after that.

I don’t understand why, though.

Weather is super cold, but there’s no moisture.

I had breaks and rotors replaced last year when I bought the car, and I don’t drive carelessly.

Any ideas of what happened?

Could you please provide more information about the brake “failure.”

Give us as much detail as you can.

Year of car, and mileage? How did the brakes fail? Did the brake pedal go all the way to the floor? Did you feel any resistance in the pedal? Did you feel any braking force at all?

Going about 25 down a residential road. Started to slowly engage the breaks to prepare for a stop at an intersection where the other road is 40mph (people usually speed though). Breaks didn’t work. Since the car was also going a bit downhill, I pressed the break to the floor and kept it there. Nothing was happening, but the car was accelerating down the hill. The e-break is difficult enough to pull, that with cars parked on either side of the street, and cars flying down the other road, I just hit the horn and prayed a little. When the ground became level, I was able to sort of coast to a stop. I continued to engage the breaks, but when completely engaged, it was as if I was barely touching the breaks at all. It slowed the car a little, but it wouldn’t bring it to a full stop. Once it was slow enough, I just put it in park and started freaking out :confused:

As was already mentioned, brake failure (or even “break failure”) can have many different meanings.

Please fill in the missing details regarding exactly what happened when you pushed down on the brake pedal, as well as what did not happen.

Also, please tell us the model year of the car, the current odometer mileage, when the brake pads were last replaced, and when (if ever) the brake fluid was changed. Without actual details, you will not get much useful help.

1999 Plymouth Breeze. Bout it a year ago at 93000 miles, it now has 103000.
Barely any breaking. No resistance. I had trouble last winter with a crappy battery and I remember what it felt like to flood my breaks (is that the right term?) but this just went straight to the floor, it was not anything I had experienced before

Sounds like a bad master cylinder.

Okay, you seem to insist on calling the brakes the breaks. Those are two very different words with different meanings.
It sounds like your master cylinder is bad. It will do this again at random times. Have your car towed to a shop and get the master cylinder replaced. Do not drive it until this is done.

I guess I’m not completely sure what you mean by the different meanings :confused:

Pushed the pedal a little to slow down to stop, nothing happened. Pushed the pedal more, and more, all the way to the floor, and nothing happened. I could only BARELY feel the car slow once it got back to level ground. Is that any more helpful?

Pads were last replaced approximately a year ago in the Fall. I’m not sure about the brake fluid, unless that’s something that’s checked when the car is serviced–in that case 3 months ago when I got my oil changed and new tires. But I imagine Wal-Mart probably didn’t check that out.

haha, sorry. I’m not very knowledgeable when it comes to this stuff, pardon my misspelling. Thanks for correcting me! This is why I come to Car Talk BEFORE I go to a repairman :confused:

Now that we have some clarification, it is fairly clear that you have–at the minimum–either a worn-out master cylinder or a brake system hydraulic leak that led to a low level of fluid in the master cylinder. However, since you claim that the brakes worked properly after that incident, the bulk of the evidence indicates that the master cylinder is worn out.

This car is NOT safe to drive, despite the apparent recovery of the brake system after that incident. The brake pedal will go to the floor again, and the next time you will probably not be so lucky.

I suggest that you have the car towed to a trusted independent mechanic for a thorough check of the entire brake system. Tell the mechanic that your brake pedal went all the way to the floor and that you had little if any braking ability. Allow him to diagnose the problem.

Even if the brake pads are relatively new, you need to have the entire hydraulic system checked, and when the work is done, be sure that it includes changing the brake fluid. Unless you get your brakes repaired before driving the car again, your car represents a definite hazard to you and to everyone else on the road with you.

Thank you very much. I appreciate your input and will do exactly as you have said.

You are very welcome.
I am glad to help, as are all of the regulars in this forum.

All the best for continued safe driving!

There’s something else you need to do that almost got lost in your original explanation: If your emergency brake is too hard to pull to be useful in an emergency, you need to get that fixed. Now. You just found out why :wink:

I too would first suspect tha master cylinder, but I wanted to add that whereas the “weather is super cold” there is also the possibility that you’ve gotten moisture in the system and it iced up.

Brakes being one of the single most critical parts in the entire car, I’d be inclined to change the MC and completely flush the system with fresh fluid. You do not want to fool with this problem.

Random failure could be caused by the rear drum brakes being totally worn out. The fluid leaks out. The problem is that the front brakes share the SAME reservoir these days. It was not so in the past when brakes used to be safer. There are other causes but this is the one I am most familiar with.

No, they don’t really share the same reservoir. It’s two different reservoirs at the bottom. At the top, it is all together, but it the front or the rear has a bad leak, it will only empty the top third of the reservoir and all of that side (front or back). The opposite side will still be 1/3 full of brake fluid.

I am going to propose that the problem could be as simple as low brake fluid.

The cold cause the fluid to shrink, exposing the master cylinder to air - and the feeling of no brakes. When the car idled, it heated up the fluid and replaced the air in the master cylinder.

So there might not be anything wrong with the master cylinder.

Had the same problem on a Ford van!

Sliding on glare ice or had left foot under the brake pedal without realizing it are also possibilities.

A little fluid runs out of the front and into the back whenever you accelerate or travel uphill. A small rise between the ends doesn’t work very well. Fixing the rear brakes fixes the problem when this is the case. Nothing like pumping air to make your day. The first time I saw one hole to service both ends I knew there would be many complete brake failures. Responsible car companies would not build anything like that.