Quote:
Originally Posted by barry12345
Maybe any dealer can tell you how many pushes of the pedal are left.  Actually this post coincides with something I earlier thought I read, It just was not clear.
There is still enough confusion to talk to a good Mercedes dealer. It may be a simple case of resetting the counting device before the unit hits its pre programmed limit. If it is allowed to do so it may not be resettable.
There has to be something there as even Mercedes could not allow the system on the road for potential liability issues unless they had an escape.
I again as it was so cloudy got the impression when they changed the fluid and bled the brakes as a maintenance item they reset the counter.
You do not maintain the car to their specifications you lose your brakes? They may have lost any liability. At the same time I would find this very strange engineering.
It also is odd that the posters message above my post was not general knowledge. I just went back and read it. Pure and simple it is designed to stop functioning. Maybe the onset warnings have been missed for those that have experienced sudden failure. If this is the case they are pretty safe systems as long as you watch for the indicators after all. I wonder how many people have decided to sell these cars when a Mercedes dealer tells them you are starting to approach unit replacement time. Nothing much surprises me anymore. |
MB dealer can actually tell you the number of actuation -- you can poll the number of actuations in the SDS.
MB used to replace the SBC when the messages showed up -- though lately they've issued a new TSB (I use the word "lately" very loosely, as they released that years ago) that basically said read the number of actuation, reset it, and then program a new software that extends the number of actuations before critical failure.
(note, the below paragraph is speculation and from my and other conjectures and is not hard fact)
The new software apparently (again using that word very loosely) changes how SBC functions which in theory would extend the practical lifespan of the pump. It also introduces new monitoring procedures that if the requirements are met, it immediately deactivates the unit. MB (obviously) has kept mum about the specifics, but our conjectures is that it monitors how much force it takes to move the piston in the MC and the amount of pressure in the master cylinder and elsewhere. If the pressure does not meet/exceeds a certain tolerance (indicative of piston wearing out or crud in the brake fluid sealing the hydraulic fluid circulation), it immediately deactivates the unit.
Keep in mind that the SBC master cylinder pressure is measured in bars, and polling the MC pressure sensor in SDS returns a number between 100-300 bar. So it's conceivable that the brake line pressure exceeds that number.
FYI: 100 bar = 1500 PSI. Water based CNC cutter use a water pressure of 1500+ PSI to cut metal.... so imagine 1500 PSI of hydraulic fluid exploding out of a brake fluid line or the master cylinder erupting under pressure---it leads to all sort of liability for MB...especially if the hot hydraulic fluid hits the exhaust manifold or the exhaust tubes.... fire, fire everywhere.
(end speculation)