Brake failure on a new car

Is it possible that a BMW 328xi that I’ve had for 8 days could have brake failure? I was parking the car in a garage when I stepped on the brakes and nothing happened. By the time the garage wall stopped the car, my foot was on on the ground on the brake pedal. I got the car with 3 miles on it and had about 350 miles on it when this happened. BMW is telling me it’s impossible but I know what happened. I just don’t know why…any insight?

Yes, it is possible. Unlikely, but possible.


“By the time the garage wall stopped the car, my foot was on on the ground on the brake pedal.”

On the ground?? Or are you trying to tell us that the brake pedal went all the way to the floor? If the brake pedal went all the way to the floor, that would seem to indicate that the car came with a defective brake master cylinder. While this is very much unlikely, it is possible, I suppose.

If it can be proved that the master cylinder is defective, then BMW is responsible for the body damage, as well as repairs to the brake system.

I meant all the way to the floor. Not strong enough to pull a Fred Flintstone!

Thanks for the info. Now I’m just hoping that it can be proven that it’s BMW’s responsibility to fix the body damage. Especially since they’ve been “holding” my car for over a week while they wait for a certified BMW engineer from corporate to come look at it and analyze the results. Who knew the BMW service center at BMW of the Main Line didn’t employ BMW engineers…

Automatic transmission? Are you saying the car was plowing ahead even with the brake pedal depressed to the floor?

I have had master cylinders fail internally where the brake fluid slips past the piston. On one car, a 1965 Rambler, the car would only do this occasionally–the pedal would drop to the floor. A quick pump would bring it back up. My mechanic could find nothing, but finally agreed to change the master cylinder. As he was pulling it into the service area, the pedal went to the floor with him.

I’ve had this happen with other cars as well, but only with high mileage. However, I suppose a master cylinder could be defective from the factory and cause your problem.

Do you mean brake failure or unintended acceleration? The latter was first reported on Audis twenty years ago. Owners reported that their cars would leap forward or backward with so much power that the brakes couldn’t stop them. What actually happened was that they floored the accelerator pedal thinking it was the brake. Common factors were automatic transmissions and new owners who didn’t drive much.

If your car simply rolled into the wall without accelerating, I agree that you have a brake problem, probably a bad master cylinder. This is unusual, but not impossible. However, if it accelerated strongly into the wall, I think you got the wrong pedal.

My friend and I were the victims of just such an incident about 5 months ago, when we were broadsided by a woman driving a Lexus SUV. She told the police officer, “The harder I pressed the brake pedal, the faster the car went”. As I surmised, and as testing later indicated, there was nothing wrong with the brakes, and the ignoramus who destroyed my friend’s car apparently did not know how to distinguish between the gas and brake pedals.

However, in this instance, I presently believe that we are not dealing with “unintended acceleration”, and that the OP did, in fact, experience brake failure. Of course, that is a preiminary conclusion based on my interpretation of the reported facts. Inaccurate reporting or bad interpretation of accurate reporting can result in a wrong conclusion, so it remains to be seen what we are actually dealing with here.

Question for the OP: Was this brake problem intermittent? Did the brakes work normally after this incident? Or did you continue to experience brake failure after this occurred?

I’d still like to hear the defintion of the pedal going to the floor. Going to the floor literally or going to the floor as in the pedal feels fine and is depressed as much and as hard as possible.

The former points to a possible hydraulic problem in the master cylinder. The latter points to driver error (as in most unintended acceleration cases) especially if the vehicle has an automatic transmission because the torque converter will not override the throttle and will simply stall out first.

How about providing a little detail OP?


If this is an attempt at humor, it missed the mark.

‘Pedal going to the floor’ when talking the brake pedal is pretty definite. Either the pedal became disconnected from the plunger or the master cylinder failed. On a new car, this is very highly improbable, but can happen none the less. The master cylinder going completely bad is the part that bothers me. All new cars have a double piston master. For both to go in a new car with less than 500 miles on it is truly astronomical odds. The dealer should be able to fix this and the body damage under warranty. Please find out what went wrong, and post the results for us.

The reason they called in the engineer is to break out the entire brake system and find out what happened. They want to definitively know what happened. If this happened on the road in traffic, people could have been killed. They want to know how this could happen to prevent it from happening again to someone else. This could very well become a recall issue.

BMW may take a look at this (entirely normal) but if there’s not a problem found then warranty is not going to pay one dime of this; nor should they.

Most of these things involve driver error and drivers will either not admit to making a mistake or in the situation may simply not even remember making a footwork error due to the speed and panic involved.

If anyone remembers the TV stories about 20 years ago involving the Audis it was determined that in every case it was driver error. Some of the drivers admitted later after thinking about it that it was their fault and in other cases the story did not gel; especially the ones who stated the engine was running at full speed and “they had both feet planted firmly on the brake pedal in an attempt to stop”.
No way is the engine going to override the torque converter.

My feeling is that BMW will get to the bottom of this although it would be helpful here if the OP would fill in a few blanks.
I don’t know how new BMW engine controls are set up exactly but one would think that it would have “black box” capability and if so that will reveal all.

I had a weird thing happen on my Buick, but it wasn’t a new car by any stretch of the imagination. I was in the garage, shifted into reverse, and the car took off as soon as I took my foot off the brake. I slammed the brakes again, but not before I took out the bottom panel of the garage door. We never figured out exactly what happened, but I am not opposed to it being partly my fault in some way, but it wasn’t a matter of mixing up the pedals since I was able to successfully brake after the bizarre acceleration in reverse.