ajoe

On the bmw 745 board, someone posted a story about a friend who was backing his new E500 out of his garage and his brakes didn't work and he rolled into a tree. He also stated that the car wouldn't restart as well. After car was towed to dealer the problem couldn't be duplicated. I don't really care about the truthfulness of this story, but it does raise a couple of good questions. Is there a mechanical backup to these electronic brakes? If you did lose power for whatever reason, are these brakes operable? Have the electronic brakes been used previously on the S class? Any answers to these questions would be greatly appreciated. Thanks.

bmms8

well all i can answer is that this is the 2nd mb to get these brakes...the first is the 2003 sl500....i dount this story is true....mb spent to much time with car to happen.....and the dealer would of found something....the bmw board is just making up **** cuz they have the reg brakes...and abs.....wait a minute, mb also made abs....hmmm...

Juke-box

umm....could it be that the new E's brakign system is a farther reach than the previous versions? i've noticed this on the first day when i stepped too hard on the brakes causing a long skid sideways through a stop sign...scared me ****less.

but the brakes work very well no doubt. i don't think this story is true. probably the driver wasn't careful

VroomVroom

ajoe - could you please post or pm me the direct link to the post about the new E and the problem?

rayscar

How can you brake too hard and cause the E to skid when it has antilock brakes??

bmms8

yea hes right, it would be pretty hard to do, even if you did skid, the system would catch that......and fix it....the bmw forum is just making stuff up.....they dont know ****.....they have to make up bs

rayscar

I don't believe either story. There has to be backup systems. For example, MB has a drive by wire prototype but isn't allowed to offer the system because they haven't figured out how it would work in case of a power failure in the car. The current braking system would also not be allowed to be used in production unless it had a fail safe back-up. Looks like the beginning of an urban legend!

Dema

I wouldn't trust any story in bmw board about mb. They are too jealous.

Kar don

there is a back up master cylinder if the electronic one fails. Also there are 2 batteries.

northbenz

Let's see. We know that there is a "back up braking system" in the brake-by-wire Mercedes. In the alleged story the Mercedes was "backing up." Ergo, the "back up braking system" would have stopped the Mercedes backing up!

On a more serious note, the supposed story does raise the question of whether the back up system is triggered only when there is a failure of the braking system while the vehicle is going in forward motion.

rayscar

I would doubt very much that the direction of the vehicle has anything to do with wether the back-up system engages or not. I'm sure the back-up is triggered by specific system failure criteria of the primary system and not with speed or direction of travel.

boltonblue

This story has an audi-esqe ring to it.

The audi sudden accelaration only happened to drivers that were unfamililar with the car. The ergonomics were different than what they were used ( ie wide GM brake pedals) and they just stomped the accelerator. once sixty minutes got ahold of the story it was a dangerous car.

probably some twit adjusting his/her mirrors while backing up and ooops, crunch. " oooh honey, I don't know what I happened. I stepped on the brakes and they didin't work"

who is going to tell their bmw friends that they were that stupid to back into a tree in their brnad new E

rayscar

That's and excellent example boltonblue. If there is something wrong here it's driver error and driver embarrassment.

ajoe

What good is a backup master cylinder if the electronic signal from the brake pedal is interupted. This is a scary prospect unless there is some form of mechanical linkage from brake to a master cylinder.

MBZman

Hi,

There indeed is a backup system to Mercedes new braking technology. Basically, the back up system is a full fledged traditional braking system. In other words, the backup system is the same as say the 2002 E class.

yipikaye

I agree with MBZman. There is emergency brake system when SBC brake is failure. This emergency mode is called "limp-home". But it think if this limp-home is oprated, there must be a warning message in the instrument cluster. Take a look at page 78 in owners manual. Read the one in the most left.

mb_newbie

According to MB service training, if the SBC fail, you won't be able to start the car and drive it (once you try to start the car, the central computer will examine all the electronic equipment, if any essential parts are mailfunction, you won't be able to start and go).

-- mb_newbie

marauder

http://bimmer.roadfly.org/bmw/forums...1093039&page=1

Sounds like the car suffered from loss of power braking and while braking was there, it was just drastically reduced, so it felt like "no brakes." The guy seems to have also panicked. I don't think it was an outright failure of the braking system and the mechanical system did its job. I wouldn't totally dismiss it, though, as first year German cars have always been known to have problems.

ValueplusClass

· In case of a serious fault, a direct hydraulic connection between the brake pedal and the front brakes enable the driver to safely decelerate the vehicle.

bmms8

i see, thats cool, it wont even start, but in some cases you would need to drive, even if they arent working.like a robber tries to rob your house, he gets away, you follow him, but it wont start cuz he cut it

Barney

That is quite the imagination! A robber coming to your house who is clever enough to open the hood of your MB, not to steal it, but to figure out how to disable the electronic break system - pretty funny.

Dema

Not exactly this case, but if you've seen movie Glass House, then your scenario is almost true.

bmms8