SBC - probably an embarassing question.

[Philnix]

Hi All,

Errr... Just been reading on "another mercedes forum" about SBC on the braking system, and that it has a fixed or limited operational life.

So, new to MB's and not terribly up to speed on all the abbreviations and the model codes, etc, my questions are :

1. What is the SBC - what does it do ?
2. Does my 2010 E350 CDi have one ?
3. If it does have a fixed service life, will replacement be covered by the warranty, and/or the monthly service plan ?

Ta in advance.

[ Just to explain - since getting the MB , took an interest in the online forums. Saw this topic on the other forum, but asking the question on this one as I have signed on to this one. Sorry if treading on any toes ! ]

Phil

 

[Dryce]

Hi All,

1. What is the SBC - what does it do ?
2. Does my 2010 E350 CDi have one ?
3. If it does have a fixed service life, will replacement be covered by the warranty, and/or the monthly service plan ?

1. An advanced braking system on W211 E class between 2002 and 2006 plus some other models (CLS, SL come to mind).

2. You don't have it.

3. The pump has a life time based on either number of brake actuations or pump actuations (it's not clear). MB replace it for free at the moment if it reaches that limit.

 

[jasonyw]

Mercedes Benz were one of the first vehicle manufacturers to employ a brake-by-wire system on a car.

Called sensotronic (SBC), the system no longer relies on the driver to produce hydraulic pressure. The
brake pedal is connected to the computer (ECU) by wire (brake-by-wire). The sensors on the brake
pedal will inform the computer how the pedal is pressed, eg how far, how fast etc. The computer will
then dissipate the required force to each wheel via modulators.

Fitted to higher end Mercedes (E Class, SL & CL Class, CLS etc) problems can occur with the ECU.

Is it fitted in your car? Check your yellow booklet that came with your car, probably not as Merc have reverted to servo vacuum due to the unreliability of SBC pump.

http://www.youtube.com/watch?v=PpvCoaRoQa4&NR=1 What model is this? No headlights.

http://www.youtube.com/watch?v=UX2Nm4a1Fwk&feature=related

http://fliiby.com/file/852272/i87jc7xjow.html

 

[renault12ts]

See post 2 for the answer.

 

[Philnix]

Thanks to all for prompt and reassuring answers.

Phil

 

[iscaboy]

Mercedes Benz were one of the first vehicle manufacturers to employ a brake-by-wire system on a car.

Called sensotronic (SBC), the system no longer relies on the driver to produce hydraulic pressure.

No car built since 1930 has relied on the driver to produce hydraulic pressure for the brakes... vacuum / servo assist.

 

[Dryce]

No car built since 1930 has relied on the driver to produce hydraulic pressure for the brakes... vacuum / servo assist.

Brake servos were not a 100% standard feature on cars even by the early seventies. Even early Capri and Mk III Cortina variants didn't have them across the range as standard.

I have a possibly inaccurate recollection that the 911 didn't have servo assisted brakes at that time as standard either.

 

[renault12ts]

No car built since 1930 has relied on the driver to produce hydraulic pressure for the brakes... vacuum / servo assist.

You better explain that pearl.

 

[renault12ts]

Brake servos were not a 100% standard feature on cars even by the early seventies. Even early Capri and Mk III Cortina variants didn't have them across the range as standard.

I have a possibly inaccurate recollection that the 911 didn't have servo assisted brakes at that time as standard either.

Not even by the late 80s!!

 

[Dryce]

Thanks to all for prompt and reassuring answers.

Phil

Reassuring in what way?

My money would be on a driver with average skills stopping quicker in a 2002 SBC equipped W211 than in a 2006 facelift W211 or 2010 W212 with BAS+ when things unexpectedly take a turn for the worse.

The system basically sits there ready to deliver near instantaneous maximum braking at all times - with control over its application at each wheel.

You don't realise just how good it is until you get caught out and it saves your day from turning bad.

 

[whitenemesis]

Reassuring in what way?

My money would be on a driver with average skills stopping quicker in a 2002 SBC equipped W211 than in a 2006 facelift W211 or 2010 W212 with BAS+ when things unexpectedly take a turn for the worse.

The system basically sits there ready to deliver near instantaneous maximum braking at all times - with control over its application at each wheel.

You don't realise just how good it is until you get caught out and it saves your day from turning bad.

Which is exactly what BAS and ESP do? SBC combined that with 'brake by wire' i.e. the brake pedal was not connected by hydraulics to the braking system. The bit that fails on SBC is the high pressure pump/reservoir that takes the place of the usual brake servo + drivers foot pressure. If the system were that advantageous/reliable then wouldn't MB still use it and introduce it across the range?

 

[jasonyw]

Which is exactly what BAS and ESP do? SBC combined that with 'brake by wire' i.e. the brake pedal was not connected by hydraulics to the braking system. The bit that fails on SBC is the high pressure pump/reservoir that takes the place of the usual brake servo + drivers foot pressure. If the system were that advantageous/reliable then wouldn't MB still use it and introduce it across the range?

If the vacuum servo can be perfected, there no reason why the sbc pump cannot.

I didn't know the sbc braking system is faster than servo until I saw the Utube clip, it all to do with the driver response not the technology.

 

[talldude]

I have SBC on my car (E270cdi 53plate) and have read the whole owner's manual. I had to do an emergency break when first got the car two weeks ago and thought the breaks were fantastic, much better than on my E300 TD, even though they were great as had the break disks/pad and break oil changed. I find the breaks different, may be missing that human touch, but when in an emergency they were great, the car stopped so quick and steady, better than the E300 would. I'm impressed.

 

[jasonyw]

I have SBC on my car (E270cdi 53plate) and have read the whole owner's manual. I had to do an emergency break when first got the car two weeks ago and thought the breaks were fantastic, much better than on my E300 TD, even though they were great as had the break disks/pad and break oil changed. I find the breaks different, may be missing that human touch, but when in an emergency they were great, the car stopped so quick and steady, better than the E300 would. I'm impressed.

Are you talking about breaking your car or braking?

Mind you language.

 

[Dryce]

If the system were that advantageous/reliable then wouldn't MB still use it and introduce it across the range?

The system is an extra expense on the vehicle and as MB were the first to use it they also took the risk (ie. possible expense) of problems down the line.

It doesn't appear to be inherently unreliable. Clearly it's not failure proof. And there have been recalls/upgrades. The pump has a life time - that depending on how the car is driven causes the pump to expire for safety reasons and require replacement.

But for MB the bottom line is whether it adds value to the car over and above the cost incurred by fitting it. Clearly it doesn't. The average owner has no idea as to what it is and what it does. I suspect a majority are unaware of the SBC-H mode - we certainly see posts here from owners who don't realise the feature until owning the car for a while. It represents a cost on the vehicle without a premium on the sale value. So MB quite coldly and logically dump it.

 

[MJH]

Admittedly I'm new to the Mercedes and it's gizmo's but within the first few weeks I've used both SBC Hold and SBC Stop and I think they are both nice features, although far from essential. As for normal braking compared to my old Landy the Merc is bloody great But, having had a variety of more driver focussed cars in which I've spent many a fast lap playing, I have to say I'm not 100% convinced by the technology taking over. I like to be in control of the car and feel whats going on, it makes driving more enjoyable. I'm of the same view with stuff like ESP, slowly technology is taking the skill away from the average driver which I think is to the detriment of overall driving standards.

I am slightly concerned to hear the pump is a possible weak point given the safety implications, do we know/have we got any figures on, what the failure rate actually is ?

Mike