Also, as you point out, car electronics and safety systems have become so complex that problems outside the warranty period are almost inevitable for both petrol and diesel cars.
An example of this is in HJ's Telegraph column today: apparently, modern Benzes have a special 'Sensotronic' brake control pump that has a predetermined lifespan of a given number of brake applications. Once this number is reached, it throws a fault code that would cause the car to fail an MOT. Even with MB goodwill, it's £900 to replace.
http://www.telegraph.co.uk/motoring/caradvice/honestjohn/10513942/Mercedes-Benz-E-Class-brakes-stopping-short.html
Thanks for that!!!!!
Remind me to cross MB off the list of cars i will ever buy, but reinforces my suspicions that cars are now being "engineered" to last a finite time, (Warranty) and not just MB.
And those who now have 1 year warranty and the following years "supported" by the dealers. Ford and vauxhall apparently.
Edited by oldroverboy. on 22/12/2013 at 18:23
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Also, as you point out, car electronics and safety systems have become so complex that problems outside the warranty period are almost inevitable for both petrol and diesel cars.
An example of this is in HJ's Telegraph column today: apparently, modern Benzes have a special 'Sensotronic' brake control pump that has a predetermined lifespan of a given number of brake applications. Once this number is reached, it throws a fault code that would cause the car to fail an MOT. Even with MB goodwill, it's £900 to replace.
http://www.telegraph.co.uk/motoring/caradvice/honestjohn/10513942/Mercedes-Benz-E-Class-brakes-stopping-short.html
Would this be any help? www.bba-reman.com/content.aspx?content=mercedes_SB...e
The whole system sounds like a cynical, over-engineered cash grab though.
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The whole system sounds like a cynical, over-engineered cash grab though.
Totally Agree.
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Perhaps MB have determined that the unit has a "safe" life, with no potential failure indication or partially failed state. So to avoid catastrophe, set a predetermined number of uses and then raise an alert in a timely manner that will only allow you to ignore it for so long (unfortunately this could be the best part of a year in UK). The alternative may be that you see no sign of impending failure, but then suffer from a total loss of servo assistance.
All it may be doing is indicating that the unit has reached the end of its predicted working life. Not too different from the wear indicators on tyres, brake pads, battery condition etc.
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The alternative may be that you see no sign of impending failure, but then suffer from a total loss of servo assistance.
All it may be doing is indicating that the unit has reached the end of its predicted working life. Not too different from the wear indicators on tyres, brake pads, battery condition etc.
Loss of servo assistance? There's no servo assistance. Your foot does not generate any hydraulic pressure with these system - the pump generates all braking pressure - should it fail and the accumulator on the pump be depleted of its reserve pressure you will have no brakes - nothing - nada. At least Citroen used to fit proper emergency brakes to their cars fitted with power braking (mechanical breaking via the "handbrake" to the front discs.)
Tyre and brake wear indicators are genuine wear indicators, this is an arbitrary figure of applications pulled out of the air. It like someone forcing you to change your brake pads after 10,000 applications of the brakes even though you only have 10% pad wear because you're a light braker.
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this is an arbitrary figure of applications pulled out of the air.
I didn't know that this is an arbitrary figure plucked from the air. I tried to find out where it came from, but could not.
How did you find out it is an arbitrary figure ?
should it fail and the accumulator on the pump be depleted of its reserve pressure you will have no brakes - nothing - nada.
That's why I suggested it would be important not to let this unit fail ie it has an expected life (number of applications), it has no evident potential failure signs, or its partial failure to full failure is an interval which precludes intervention. If you identify the appropriate reliability pattern and have sufficient empirical data to suit the component, a wear out point could be specified and a safety margin introduced, agreed this will not hold for 100% of cases, there are various engineering solutions to this and my suggestion was that this is what may have happened. The reason I mentioned the tyre and brake wear indicators is that they are indicators that you can see and you base your interventions around, likewise the research carried out to give the intervention time for the braking system may be just as visual, just not to you.
My view was only a speculative view. It has the feeling of a hard time maintenance task derived empirically, or maybe they did just use chicken bones and hallucinogenic drugs.
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I'm sure if you changed your brake fluid every year the pump would last practically forever, it's a similar situation to the WABCO system fitted to MK2 Range Rovers the pumps usually fail due to neglected fluid changes (pre-99 failed plastic brake valve apart).
Even if maintained to MB service intervals I suspect the brake fluid moisture contamination will be sufficient to start causing wear in the pump. That's why it will be an arbitrary figure that bares no relationship to the actual condition of the pump or the servicing (or lack of) the brake system has been subjected to. Why have a number of depressions limit? Surely you can tell the pump's condition by it not being able to reach a certain pressure within so many seconds of activation? As well as how much current it is drawing? The number of depression "solution" is depressingly low-tech and arbitrary - it smacks of - well, I was going to say poor engineering but I won't even afford that lash up with the word "engineering" in the description. Lash-up is just fine, But who cares? The second private owner gets to pick up the bill.
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Again the word "arbitrary" is bandied around with no supporting evidence.
To know why this figure is used, we would need to know the failure mode(s) that this maintenance is addressing. It may not be wear owing to water contamination. It may not be a function that can be diagnosed by measuring the currrent drawn or speed of reaction (this kind of failure finding is as good as useless depending on the p-f of the component), what if it were owing to mechanical component failure through cyclical stresses, how would you diagnose this impending failure and how much would it cost? If the figure is arbitrary, at what point would you start the fault finding process, every 10K, 20K, yearly, 2 yearly etc? How much would these cumulative diagnostic events cost before the unit is found to be at risk and will have to be changed anyway?
My position is, once again, that you are coming up with judgements - not even opinions - without fully understanding the issues at hand or having the knowledge of the system necessary.
I used to keep my new cars for up to 2 years. I would not have to fit new tyres, pads, discs, batteries, cam belts, aux belts, pollen filters, clutches, plugs, coils etc, but undoubtedly subsequent owners would.
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Again the word "arbitrary" is bandied around with no supporting evidence.
To know why this figure is used, we would need to know the failure mode(s) that this maintenance is addressing. It may not be wear owing to water contamination. It may not be a function that can be diagnosed by measuring the currrent drawn or speed of reaction (this kind of failure finding is as good as useless depending on the p-f of the component), what if it were owing to mechanical component failure through cyclical stresses, how would you diagnose this impending failure and how much would it cost? If the figure is arbitrary, at what point would you start the fault finding process, every 10K, 20K, yearly, 2 yearly etc? How much would these cumulative diagnostic events cost before the unit is found to be at risk and will have to be changed anyway?
My position is, once again, that you are coming up with judgements - not even opinions - without fully understanding the issues at hand or having the knowledge of the system necessary.
I used to keep my new cars for up to 2 years. I would not have to fit new tyres, pads, discs, batteries, cam belts, aux belts, pollen filters, clutches, plugs, coils etc, but undoubtedly subsequent owners would.
How many other manufacturers have this requirement to renew, as routine maintenance and at great expense, a major part of the braking system?
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How many other manufacturers have this requirement to renew, as routine maintenance and at great expense, a major part of the braking system?
Simple answer, I don't know, but....
How many other manufacturers use this system, that requires this maintenance?
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That MB system was a short lived huge mistake, it was i am almost certain only fitted to W211 E class between 2002 and 2006, and was dropped for 06 on facelift versions.
Up until recently MB would replace these pumps on a goodwill basis, but that seems to have been quietly dropped.
If they do fail, you are left with some brakes, roughly 10% which is worse than the loss of servo on a normal braking system.
The problem with buying this model used is that its possible to reset the ''countdown'' electronically, and you, the used buyer, have no idea if this has been done instead of a replacement pump.
Facelift W211 E class is widely regarded as a very good car, almost all the earlier models foibles were ironed out as well as this pump issue.
I know the boss of a very good very old school private hire company who until he changed them (for the latest W212) recently ran W211, 220d's, both cars went over 400k miles with few faults but were maintained exlusively and properly by the MB indy workshops i use....the taxi drivers he uses are also the most professional you will witness, his cars stand out from the crowd by good driving standards as well as being spotlessly clean at all times.
Edited by gordonbennet on 22/12/2013 at 19:35
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Yes, I've heard the current E-class is earning some of MBs deservedly lost reputation back.
My understanding is the Sensotronic brake potentiometer has no physical connection to the hydraulic circuit - how can it be generating braking force? Unless your 10% is roughly what's available from the accumulator after brake pump failure?
Assuming you are physically strong enough to push the brake pedal hard enough on a conventional system - the loss of the servo-assistance will not lose you any potental braking effort it'll just make it harder for you to generate that pressure.
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This bosch sbc braking system was also fitted to the SL R230 chassis models of a similar age.I t is similar in operation to the ford system used on the Scorpio in the 1980s.What I find more worrying ,is the frequency of very expensive repairs needed to modern cars when they are recently out of their warranty period.I. Have been in the motor trade for over 40 years and have never seen so many late cars with engines/gearboxes in pieces,and not covered excessive mileage.We are talking here of premium ? brands.MB,BMW,Audi and even Porsche.I often wondered what would happen if you sent a problem car back to the manufacturer to see if they could sort out any problem easier than the dealer.Somehow I doubt It,even though they made the thing in the first place.Just an observation .
Edited by elekie&a/c doctor on 22/12/2013 at 20:04
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'''My understanding is the Sensotronic brake potentiometer has no physical connection to the hydraulic circuit - how can it be generating braking force?''
I don't know and i'm only going by reports of failure, fortunately seem to happen at low speeds, from poster on one of the MB fourms i am a member of.
Its not something i would buy into, the early W211 also had its fair share of other electricla problems too.
Thanks to E&AC Doc, didn't know the R230 had the SBC, so between that, the airmatic problem suspensions @ £1000 a corner and loosening baffles in the fuel tank, would you advise getting one at my earliest convenience?...;)
My MB indy's workshop has been an eye opener for me, he had 2 V12's stripped out there at one time both suffering from a resurgence in the Black Death of Ford CVT days.
My W124 is quite modern enough for me thanks, specifically sought out because it wasn't specced up with electronic extras, each waiting in turn to present themselves with a large invoice for repair attached, would no doubt be linked to with disdain if i advertised it as 'poverty spec' by those who need toys.
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I often wondered what would happen if you sent a problem car back to the manufacturer to see if they could sort out any problem easier than the dealer.Somehow I doubt It,even though they made the thing in the first place.Just an observation .
Agreed - in some cases, problems seem to stump the manufacturers themselves. The internal pressures from sales and marketing, combined with external pressures related to emissions and safety, are trumping good engineering sense.
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anyone have any problems with the ford econetic diesel engines? not sure if upgrading to an econectic fiesta>
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anyone have any problems with the ford econetic diesel engines? not sure if upgrading to an econectic fiesta>
See in Technical. Be very careful!
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The whole system sounds like a cynical, over-engineered cash grab though.
Totally Agree.
The trouble is, even if you were a methodical person and researched your cars thoroughly, it could take a while to discover this little gem.
I would be quite annoyed to find out later that I owned a car with such a needless system.
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The whole system sounds like a cynical, over-engineered cash grab though.
Totally Agree.
The trouble is, even if you were a methodical person and researched your cars thoroughly, it could take a while to discover this little gem.
I would be quite annoyed to find out later that I owned a car with such a needless system.
Anyone who did any research at all would avoid a MB of this era: lots of faults etc well documnetd on this site and others.
Most people do no research and buy on colour and reputation ...Hence people complaining afterwards about features they don't like or having features they don't understand as they are too dumb to RTFM...
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The whole system sounds like a cynical, over-engineered cash grab .
Most people do no research and buy on colour and reputation ...Hence people complaining afterwards about features they don't like or having features they don't understand as they are too dumb to RTFM...
Exactly.
I know what i want from a car.
Aircon.manual.acceptable seats.petrol.
Rest is down to what is available in budget with research, obviously.
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