(!) Brake Service, Visit Workshop

[y13pmc]

hi isnt it strange must be something in the air this week
went to have my e320 4 wheel tracked drove it onto the ramp brake warning light came on visit workshop and then restart car to i suppose reset had the job done backed of ramp no light what i have noticed is when hard braking wheels skid very sharply as if abs is not working STRANGE

 

[Dieselman]

Mercedes must be ruing the day they fitted SBC to cars.
Having been their most expensive re-work ever, it's going to cost another fortune now all the units are ageing.

 

[Dryce]

Does this only affect pre facelift w211's? or all?

Only pre-facelift.

MB downgraded the brakes on the post-facelift by removing the SBC system.

 

[Dryce]

Mercedes must be ruing the day they fitted SBC to cars.
Having been their most expensive re-work ever, it's going to cost another fortune now all the units are ageing.

Question is how much do the pumps actually cost. My guess is that the if they simply offered them at a reasonable price people wouldn't be so concerned and MB wouldn't end up paying.

Instead they charge an exhorbitant amount for the pump and then do free replacements ..... DOH!

 

[Smiley]

Only pre-facelift.

MB downgraded the brakes on the post-facelift by removing the SBC system.

I think it would be better to say that they downgraded the brakes when they fitted SBC.

 

[donubenz]

I really like the system on my 320cdi.
Holds at lights with SBCH so no creeping
Brakes really well with great assistance if you need to shove the pedal hard.
Mine also has a feature for town driving so that if you click the cruise on when stationary you get SBCS. This allows you to drive and stop with the accelerator, press to go and brakes when you take you foot off, great in traffic when you get used to it. It drops out above 35mph ish with a ping to let you know its gone and the dash display clears. I assume not many know of this feature?
Don

 

[Dryce]

I think it would be better to say that they downgraded the brakes when they fitted SBC.

Ever actually experienced SBC in action?

MB SBC equipped cars might be troublesome to MB but I know which I would prefer with a carload of people and something bad unfolding in front of me.

 

[Dryce]

I really like the system on my 320cdi.
Holds at lights with SBCH so no creeping

Facelift W211 has a brake hold function too. Different implementation.

Mine also has a feature for town driving so that if you click the cruise on when stationary you get SBCS. This allows you to drive and stop with the accelerator, press to go and brakes when you take you foot off, great in traffic when you get used to it. It drops out above 35mph ish with a ping to let you know its gone and the dash display clears. I assume not many know of this feature?

These features were dropped around late 2004.

The main advantage of SBC is that life limited pump keeps the system charged and full controlled and distributed braking force is available when the system decides it wants it kicked in and it tries to instantaneously peel your face off.

 

[Smiley]

Ever actually experienced SBC in action?

MB SBC equipped cars might be troublesome to MB but I know which I would prefer with a carload of people and something bad unfolding in front of me.

Except when it has failed when I would prefer the good old fashioned system.
Anyway I am not sure that an SBC equipped car will stop any quicker than a non SBC car?
If SBC is so good why did it get removed?

 

[davidjpowell]

Except when it has failed when I would prefer the good old fashioned system.
Anyway I am not sure that an SBC equipped car will stop any quicker than a non SBC car?
If SBC is so good why did it get removed?

Because it's unreliable...

I miss the hold function.

 

[st4]

I've had the message flash up once but dissapeared just as quickly as it came and it hasn't been seen since (many, many months ago)

A low battery will also trigger the error message as well as an ESP fault/ABS sensor failure,.

 

[Dryce]

If SBC is so good why did it get removed?

Cost vs. benefit.

Costs MB to stick it in the car. Perceived benefit by customer (most haven't a clue it's there) is low. So no price premium.

So MB make no money off it at time of sale.

And it's a complicated system that's required updates (some minor).

Again a cost to MB.

I'd love to see a test of a facelift and pre-facelift W211 side by side in different braking situations. I have no doubt the pre-facelift version will 'win'.

 

[st4]

Yes, the SBC motors will exact a greater force than the servo if you like. They stop unbelievably quickly. I've done, on private roads, big speeds and big braking, and it tears you face off.

 

[Smiley]

Because it's unreliable...

I miss the hold function.

Quite.

And what's the last part of the whole car that I want to be unreliable?

That's why MB got rid of it.

 

[Dryce]

Quite.

And what's the last part of the whole car that I want to be unreliable?

That's why MB got rid of it.

It's not unreliable. There would be a scandal if it was.

It does cause problems for MB because the pump that drives the system has a lifetime (hint ... why? somebody set a conservative limit to make you swap it). It uses software. They have tweaked it.

From a manufacturer's perspective any additional component or system on the car has to justify its presence - either to meet mandatory standards, customer expectation, or to gain a market advantage.

The extra performance of SBC gained MB no market advantage. So it's just an added cost to them. So bye bye.

 

[st4]

It's not unreliable. There would be a scandal if it was.

It does cause problems for MB because the pump that drives the system has a lifetime (hint ... why? somebody set a conservative limit to make you swap it). It uses software. They have tweaked it.

From a manufacturer's perspective any additional component or system on the car has to justify its presence - either to meet mandatory standards, customer expectation, or to gain a market advantage.

The extra performance of SBC gained MB no market advantage. So it's just an added cost to them. So bye bye.

They never fail, they provide a prior warning well before the pump fails.You'll get the error message, long before the pump fails.

And there is a back up circuit, ok its unassisted but you can with two feet (thats why the brake pedals in automatic cars are so oversized) exert enough force to stop the car.

The pump lasts the average driver 100,000 miles - 120,000 miles. In that time the car will have snapped its suspension springs, gone through a turbo seal (V6 model) or several sets of sparking plugs.

Its an electrical motorised pump, and as such has a finite life like oil etc.

When SBC was introduced it gave the 211 and 230 cars stronger brakes, and more inbuilt consumer features like SBC-H and SBC-Stop. Now with distronic and brake assist the same features can be inbuilt without such a complex advanced system.

 

[Dryce]

They never fail, they provide a prior warning well before the pump fails.You'll get the error message, long before the pump fails.

I would be careful with the use of 'never'. Clearly the pump can fail - it's an electromechanical device.

The engineers' sensible solution to reduce the risk of failure has been to provide an artificial lifetime.

However the risk of failure of an additional component or components in the system has to be balanced against the relative risks of other systems failing.

And you have to factor in the benefits of a better performing braking system.

My observation would be that incidences of SBC failure are very low - and the consequences of those failures not always major. Incidences of SBC saving the day are likely to be higher frequency - and the benefits of those 'successes' frequently major.

 

[st4]

I would be careful with the use of 'never'. Clearly the pump can fail - it's an electromechanical device.

The engineers' sensible solution to reduce the risk of failure has been to provide an artificial lifetime.

.

And...

And there is a back up circuit, ok its unassisted but you can with two feet (thats why the brake pedals in automatic cars are so oversized) exert enough force to stop the car.

.

So its fine. No matter what, you'll stop.