SBC: The Ticking Time-Bomb

[Dryce]

Not clear whether you mean the posts or the systems self correct.

The 'intersesting' aspect IMO is that the pilots have different understanding of the systems they deal with ......

Nett nett, I think it' about whether a high level of computer driven automation has improved safety, convenience (operating minima) and the operating experience or not. In commercial aviation I would say it is clearly the case that it has.

Loads more aircraft, loads more flights, loads more passenger-kms.

Accidents are still newsworthy.

I think the industry has something to be proud of.

In cars.....?

Well SBC is an interesting example of the problem.

Add in some complexity and associated risks. But also with some benefits. People complain about the warning messages or failures - but don't tend to report when the system saved their day.

I think there are two occasions in the 6.5 years I've had my car that it's definitely saved the day.

How do I offset that infrequent and unproven benefit against the even rarer one where another driver has a catastrophic problem?

Well insurance is supposedly based on the reality of claims so maybe it offers a clue. So far the insurance costs on my W211 have been unexpectedly low compared with other vehicles on which I have obtained quotes over the years. That tends to suggest that SBC isn't a problem.

Does that mean it's definitely a benefit - not by this crude measure - because any statistical effects may be down to other engineering aspects or ESP rather than SBC.

 

[mejermy]

So we largely agree, but I'm surprised you feel that SBC has saved the day a couple of times. ABS yes, and I won't now have a car without.

Anyway the thread is meandering.......

 

[Stratman]

Out of interest, does anyone here know what SBC does that ABS doesn't, apart from time out?

 

[mersum1es]

Out of interest, does anyone here know what SBC does that ABS doesn't, apart from time out?

A lot.
Mercedes-Benz Sensotronic Brake Control (SBC)

 

[MicB]

Too much paranoia about sbc......there must be hundreds of thousands, probably millions of sbc cars happily being driven around world wide (many will be taxis).......the vast majority of drivers of sbc cars will not be visiting forums and consequently oblivious to the issues perceived by visitors to forums.

I do not want the expense of having to replace my sbc pump but in reality if the cost, as Olly suggests, is down to about £800 it is manageable in the context of many consumable items......a decent set of tyres is a similar cost and much more frequently required......how many discs and pads are required for every sbc pump?......general servicing is a consumable cost.

The truth is that this issue would not be exercising my mind at all were it not for the fact that I am aware that many have had their sbc pumps replaced foc......therefore I would like mine replaced foc when the day comes......but It is looking like I will have to pay.

For the record my SL is over 9yrs. old and has done 82k miles and is on its original sbc pump (I do not regard this as a safety issue......that is just scare mongering).......it has however worn out more than £3k in tyres and more than £1250 in consumable brake related parts and labour......plus servicing.

Mic

 

[SavMan]

Problem when you take that equation to a 10 year old E200 which can be bought for £3.5k.

I have always thought that the real costs for SBC will drop and drop once MB stops paying out, it will take a while and the unfortunate ones are the ones that have the problem during the current period. Once more and more are fixed outside the dealer network I can see the cost closer to £600.

 

[Dryce]

So we largely agree, but I'm surprised you feel that SBC has saved the day a couple of times. ABS yes, and I won't now have a car without.

Anyway the thread is meandering.......

I don't think you quite understand what SBC can do when somebody else makes a decision that forces you to stop in a hurry.

 

[mejermy]

Who knows, you may be right, but my MB brakes pre ABS and, since 1986 (for me), ABS, have done the job perfectly well. I'd be happy to continue with that system (which I have on all the other ones I have) and dispense with a system which is too clever by half. Funny how the oether premium brands didn't go down the same road. In fact didn't MB chuck it out after 2006-ish??http://www.mbclub.co.uk/forums/images/smilies/wink.gif

 

[Dryce]

Funny how the oether premium brands didn't go down the same road. In fact didn't MB chuck it out after 2006-ish??

How many customers even realised what the system is there? So marketing benefits against cost of fitting. Zilch. They can't charge extra for it. But it does cost to put into the car. So MB's bean counters see there is no benefit to MB.

This isn't exactly unusual with consumer products. Things tend to get pared down to the lowest level. The trick is to make the product just good enough to sell by whatever measure of 'just good enough' is appropriate.

ABS by itself is overrated. It doesn't stop you quicker and in order to benefit you need an escape route (not likely in congested traffic) - and most drivers don't put enough brake input or steering input into their response to get best use of it - and some even reduce braking input in response to the pedal feedback when it activates (DOH!).

I wonder which saves more good days from becoming bad? BAS or ABS?

 

[bpsorrel]

How many customers even realised what the system is there?

True. When I bought my S211 a few years back I had no idea what braking system it had. It was only when I joined here and started learning about the car that I found out. But, I didn't know about the expiry of the system until a while ago when I noticed a thread about it! Had I known, I probably would have avoided a car with SBC.

And yet my S211 was a great car, better than the MBs I had before it and after it....

Maybe a little knowledge is not a good thing...

 

[BlackC55]

I now have the coding info for re-setting the "service brake visit workshop" warning.

I have not tried it yet. If anyone would like me to try on their car I can do.

 

[Dieselman]

I don't think you quite understand what SBC can do when somebody else makes a decision that forces you to stop in a hurry.

So what can SBC do that other brake systems can't?

SBC is just a power braking system with the same functionality as other braking systems, but not requiring direct effort from the driver to apply the required pressure.

 

[Dieselman]

How many customers even realised what the system is there? So marketing benefits against cost of fitting. Zilch. They can't charge extra for it. But it does cost to put into the car. So MB's bean counters see there is no benefit to MB.

How do you know that? I suspect SBC is no more expensive to make in volume than the twin servo system used for BAS.

It may have been more expensive initially , due to being produced in relatively low numbers.

 

[Dieselman]

The vast majority of reports relate to the warnings - not actual failures.

I'll repeat. There have been complete system failures, which is why the recalls were put in place.

SBC was withdrawn because the post sales cost to MB was huge, the highest cost of recalls and service upgrades ever.

 

[MB-BTurbo]

What models were fitted with SBCs? E class, SL, CLS, Maybachs...any others?

 

[Dryce]

How do you know that? I suspect SBC is no more expensive to make in volume than the twin servo system used for BAS.

It may have been more expensive initially , due to being produced in relatively low numbers.

Well MB don't seem to want to provide the replacement pumps at a particularly attractive cost ....

It's likely that when they designed it in they had some assumed costs based on assumptions about volume production for the components. That's certainly the approach taken when I've been involved in hardware designs in years gone by where the initial cost is high and then costs per component drop as volumes go up. There are risks in that and they presumably didn't pay off this time.

 

[Dryce]

I'll repeat. There have been complete system failures, which is why the recalls were put in place.

I didn't suggest there hadn't been failures - however the majority of reports so far in places such as these forums relate to the warning messages appearing and pump replacement - not actual failures.

 

[Dieselman]

Well MB don't seem to want to provide the replacement pumps at a particularly attractive cost ....

That's a completely separate issue, but at about £1000 +, they aren't particularly high priced compared to other parts.

 

[Dryce]

So what can SBC do that other brake systems can't?

SBC is just a power braking system with the same functionality as other braking systems, but not requiring direct effort from the driver to apply the required pressure.

In the case of SBC the control and feedback have been taken one step further and are handled by the electronics.

The primary advantage is the speed and force with which the brakes are applied - and the control over the braking force to each wheel provided during that application. That saves on vital stopping distance.

 

[Dryce]

That's a completely separate issue, but at about £1000 +, they aren't particularly high priced compared to other parts.

Well the underlying question is what do they *cost* as opposed to what are they sold for.

If the cost a major proportion of what they are sold for then that says MB have been very kind about the free replacements but makes the decision to design in the component in the fisrt place suspect.

If teh cost is a minor proportion of what they are sold for then that says MB have been a bit disingenuous about the goodwill aspect and a bit disrespectful to the customers paying the full price.