With the deluge of W211 E Class models on the market today, they can be had for a very reasonable price, and I'm seriously considering purchasing one. However the one factor that concerns me the most is the SBC drive-by-wire braking system in these cars and the ongoing problems associated with the system.

I know there was a recall in '04 to address the problems but it seems all the kinks have not been ironed out. In fact it appears that MB is now calling the system Electrohydraulic Brake Control (which seems to be a distinction without a distinction) for the '06 MY which is essentially the same braking system. I assume either Bosch was canned or the change was made for legal purposes.

Also, with the mid-year W211 face lift in the next few months, MB will scrap the brake-by-wire altogether and revert back to a traditional braking system- excellent decision IMO but what about all the aging SBC systems?

This has me wondering why Mercedes Benz would abandon a brake technology that cost $150 million to develop, after only 3 years in use? Unless of course it's because there are still problems with the system and they expect more to crop up as the years pass. I'd even wager that you'll see another recall for this brake system.

I really love the look and style of the W211, but the potential prospect of a massive repair bill for an out of warranty braking system has me thinking twice.

I would appreciate any thoughts on this matter from anyone who has any knowledge regarding the topic.

Thanks!

__________________
-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi

IN 10 years that system will make those cars worthLESS! most have had at least 3 recalls & still the system malfunctions!

The 2007's WON'T have SBC.........The new S-class doesn't have SBC....

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Hi Paul -

Can't say I've put a tremendous amount of thought into it, but here's my $.02. I'm planning to skip owning the 211, largely because of SBC. I read long ago that SBC makes it impossible to perform your own brake work; access to the HHT (or similar) is required. So no more $100 brake jobs on this car. I've only driven a 211 briefly, but I very much disliked the subjective feel of the brakes. The pedal had an artificially heavy feel, and the relation between pedal force and decelaration was non-linear. Made it difficult to drive smoothly.

I'm not quite as pessimistic about reliability. ABS brakes have not proven to be problematic. That said, I'm sure an SBC repair would exceed the value of the car! Given that SBC has come and gone in a few short years, on only a few model lines, I suspect many independents won't be willing/able to work on it - so dealer service only?

- JimY

Scary stuff, never liked the idea or the system, hated the feel of the pedal.

Don't like the idea of the shede tree guy getting hurt trying to replace the pads in his driveway.

It looks to me like Mercedes wanted to have the monopoly of dealer only brake service, but now that the problems are mounting, they will play stupid, act like nothing is wrong and try to forget about it and sell you a new model.

Someone at Daimler/MBZ had a dream about 'wouldn't it be nice if driver reaction time was reduced when maximum braking was needed--that few feet saved might make a non-accident out of an accident'---- and SBC was born--as the first step toward fully automated braking (and spacing ) control. Well, if you have the budget of NASA, and are willing to accept the fatality rate of space program (+/- 8% death rate for astronauts), then lots of things are doable.

Unfortunately, mass produced automobiles , in everyday driving service, are not a viable platform for such sophisticated (and marginally beneficial) technology. THe cost/benefit analysis MUST have been 'cooked' to allow it. The failure rate analysis must have been a 'dream-world' analysis rather than a real-world failure analysis. I know how difficult and costly it is to get industrial process control systems to meet <1 in 10 million failures. Now--imagine--say there is 500,000 of the cars on the road everyday, and brakes are applied a total of 5 times per trip, 2 trips/day(to-from) Thats 5 million brake applications/day and therefore one could expect (of a 1 in 10 million system) a brake failure every other day. Failure could be benign or total. Now extrapolate that to 50 million vehicles--that's 50 failures/day and one would expect a significant portion to be total brake failure leading to accidents--both minor and major, depending on speed.

For a single car, it may mean you could expect (assuming 1000 trips/year, 5 brake applications/trip) a brake failure every 200 years--which seems quite acceptable. However, an automotive system like SBC is highly unlikely to reach even a <1 in 100,000 failure rate when new,considering the lack of routine performance testing of the system with off-line diagnostic tools. This leads to an expected failure rate of once/20 years. Still not too bad---but things deteriorate, and there is no programed preventive/renewal maintenance requirement like there is for industrial safety systems because it would be extremely costly (several thousands of dollars/ test and inspection/renewal) probably. So after 3-5 years, the failure rate may well be up to 1 in 10,000 or even higher. That is a failure every other year--with say 50% resulting in a collision from no brakes. hardly a comforting thought.

In summary, SBC is a great idea hunting for a need. A lot of very expensive hardware and software with really limited potential benefits, and lots of downside exposure when failure rates escalate as the system ages.

Here's what it says at MBUSA Web site regarding new S-class

So, how is that different from SBC except for the name?

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

I have a 2003 E320 211. Brakes work great. Never had a problem. Yes, there have been recalls but for obscure things. One of them involved putting a 10 cent plastic cable tie on the cable to SBC pump (and a metal thing for it to attach to) so that it would not get unplugged easily. Another was to provide something after hundreds of thousands of brake applications which was really only ever reached by taxi drivers in Europe. People also complained about the noise that the pump makes but I never thought it was excessive. I am not sure it was a recall, but if you complain, they put a damper on the pump to cut down on the noise.

Again, the system works great, I have had zero problems after 25,000 miles.

Some people complain about the feel of the brakes. After a few miles, I doubt if you notice the difference unless you want to notice it. It may not be quite the same feel but you get used to it. My wife has never, ever said anything about the brakes feeling different.

Although I have read of problems, I have never met anyone who has had SBC system problems. But I have heard of problems with more conventional brakes so I suspect all systems have some problems.

Only thing I dislike about it is that if you change your own brake pads, you have to do it in a certain way to avoid blowing the pistons out of the brake cylinders or getting your fingers pinched. But even with this, there there is a way to do it safely and if you are interested, I can provide the links to doing it without any specialized equipment including the Mercedes official way (others have a more simple way).

I am not sure of the cost benefits of the system but Mercedes claims it only costs a few dollars extra for the system but that may have been before the recalls. And if I had the choice, I am not sure I would want it but it does work great.

In short, do not worry about it. If you drive the car and like it, buy it. If you are really worried, buy an exteneded warranty. I have an extended warranty but not because of the SBC system. There is a lot of other electronics in the car that are just as complicated or more complicated and if you are worried about SBC, you should be worried about those systems as well.

Thanks all for the input. MBDOC confirmed some of my suspicions but it is also good to hear from a regular user that the complaints may be a bit overblown .. at least in the car's early years. Again, my concern would be when the brake system hits 70/80/90k miles when the car is out of warranty and you have brake trouble codes going beserk.

Kent: The system is not your traditional brake system where the pedal force that you feel is the actual force being applied to the discs. The feel is simulated because the brakes are applied electronically. From another website ... here's a good explanation of SBC:

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When a driver presses the brake pedal, his foot moves a piston, which is connected to the brake booster and master cylinder.

This means: The firmer the push, the higher the pressure in the brake lines, and the higher the force exerted by the brake pads onto the brake disc. A simple principle. With Sensotronic Brake Control (SBC) there will still be a brake pedal and master cylinder, but there are quite a few differences as well.

Because the driver's brake commands are processed by a computer, which also continuously receives sensor signals from each individual wheel and the steering system. From these data the optimal brake pressure is calculated for each wheel individually. And this, promises Mercedes, is advantageous, when braking with full force, when braking in curves or on slippery surfaces.

The driver doesn't feel any of this. The push onto the brake pedal feels like it always did. But starting from the master cylinder it doesn't continue hydraulically, but electronically. Sensors obtain the pressure and the speed, with which it builds up. This information is passed electrically to the controller, which then calculates the brake force - as described above. If the electricity fails and SBC stops working, the good old hydraulic will be used instead, and the car decelerated via the front wheels.

__________________
-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi

If you want MB's description of SBC, here is a link:

http://www.mercedestechstore.com/pdfs/W211_technician/319%20HO%20SBC%20(WJB)%209-30-02.pdf

I've read all of the-sky-might-fall posts on this subject and I think pfphipps' is the only one that makes sense. First, this little issue has cost MB a lot of money, both in warranty claims (valid or not) and in public relations. And they decided to put their engineering money elsewhere. I have direct personal experience with only one car with the system. My friend SJB picked up a new W220 S430 at Sindelfingen in it's first year ('99?) and drove it until late '02 when the depreciation had reached $1000 per month and decided to call it quits. So he swapped it for a new W211 E500 and after 3.5 years still loves the car, despite it's numerous electronic glitches. BTW, he has said that the E500 does everything the S430 did and does it better.

He has had zero problems with the braking system aside from some warranty upgrades. I've driven the car several hundred miles and don't find the brake feel much different, if at all, from my '01 C320. Which is to become, by the way, a W204 '07 C350 as soon as they show up.

As far as DIY brake pads at home, these newer cars don't seem to eat brakes like the older stuff. At 43K miles, my car has about 33% of the pads remaining. And I make no real effort to conserve the brakes.

I do think that getting someone else to pay the repair bills on any late model MB is a good idea and would recommend an extended warranty. Very carefully chosen.

I paid $2300 to double the FACTORY warranty to 8/100K miles (not Starmark, which I think has a new name, now) and don't expect to pay for anything except routine service from now on.

__________________
Roger E.

Forgot to say that SBC and BAS are not the same. Brake Assist has been standard for at least five years on even the bottom-feeder models like my C320 and I think the W140 had it earlier.

__________________
Roger E.

SBC is dead because consumers are scared of it.
The system can save the buns of an "average joe" who may not bury the brake pedal far enough to activate BAS.
It does have a artifical feel and the pedal doesn't pulsate when ABS is active,
so people think it is broken.
If I had a dime for everytime I heard "well, my Lexus doesn't do that when
I hit the brakes.", I could buy a Maybach. (which has dual SBC systems!)
SBC is cool technology that is a few years too early and way way too expensive.
The original plan was to have other car companies share the expense of
development, but nobody did. It cost MB a ton of money to develop and
now they have to walk away from it.
It's too bad. I have found the SBC features to be very helpful when the
car is in need of ESP intervention or even just old ABS, Very smooth and
stoping distances that make your neck hurt.
Pre-filling, Soft stop, Brake drying, and other features were very good ideas.
The idea was always about saftey first, not making it a scam.The system is very precise when it comes to service and can be very very
dangerous to untrained people. But it isn't a monopoly.
I will miss SBC when it fades away in the next few years for being the system
that "could have been."
DR.D

__________________
Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?

SBC is dead because the system manufacture said no more to the cost VS results,

The system will render most of the car to be worth much less due to "dealer only" repairs & related costs! How many other cars have to have the system turned off to install PADS & ROTORS safely? and require a $20,000. scan tool to bleed the brakes..SBC has nothing to do with the system going into full ABS quicker!!! That has been done by BAS since 1998 here in the USA.

SBC cars don't stop in less distance OR quicker than a regular ABS equipped car can.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Wow, I guess you don't like SBC very much M.B.DOC.
I still think it had more potetial. But, I am glad to see some of it's
features live on in the new W221 S Class with standard brakes.
We sure see less cars with SBC rear-ending other cars compared
to older E's and SL's with standard brakes.
Too bad.
DR.D

__________________
Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?

Doing a little thread digging here...

My father is looking at trading his S-Class for a W211 and I am helping him do some research on these cars. I was wondering if in the 6-7 months that have passed since this discussion - has anything changed?

Should he avoid the SBC system on the 03 - 06 models and head straight for an 07? Does anyone have a link or links to the various recalls about this system?

How about the pad change instructions (aka. putting the system to "sleep") MB DOC could you PM them to me??

Thanks a lot!

__________________
Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE