dis6933

Hi

Have a 2005 SL 500 - had for 8 years. Recently noticed that after sitting for a few days, when opening the door, a relatively noisy pump (?) would start up and run for 20-30 seconds. Suspension is not sagging and aromatic is OK.
A manual states that the pump is to run only when the engine is running, so as not to be intrusive, but I am not sure they were talking about the same pump.
Any one have any ideas of what it is and what may be wrong?

Thanks

Don

next2pool

I suspect that is the SBC or brake pump. After it shuts off, press the brake pedal with the ignition on but the engine off. See if that is the same noise. if it is, the door wakes up the brake circuit and turns on the pump if needed. Normally it doesn't activate the pump until you depress the pedal unless it is bleeding down for some reason. It could be a bad accumulator.

carguyshu

The SBC (sensotric brake controller) runs when you unlock the door and periodically after every few times you brake (that's why when working on the cars brakes you deactivate the system so that someone doesn't accidentally unlock it or open a door activating the pump). They make an updated hose that reduces the noise. The noise is 'normal,' but it is certainly annoying.

dis6933

Thanks for posting. How does one deactivate the pump to work on brakes.
I have changed brake pads, but never bothered to deactivate anything.
Don

carguyshu

Then you did it fairly dangerously. If someone would have opened the door or done anything else to activate the system with your fingers in there they would have been crushed. You can either use a STAR tool to deactivate it or you can disconnect the wiring going to the pump (it is near the front passenger side) or disconnect both batteries. In theory you are okay if no one unlocks the car or opens the door or pushes the brake. To me it is not a risk worth taking when you can easily disable it.

dis6933

Thanks for the comeback. It is interesting that after owning a car for 8 years
one discovers such a hazard. I wonder if I missed something in the owners manual, which I have read carefully and have not found any reference to the SBC system.
I also have not been notified about the recall of the system.

Don

carguyshu

There wasn't a recall, but there was a warranty extension of 10 years on the system. After so many brake pedal pushes the system will shut down and a big warning will come up on the dash and the pump will have to be replaced, which isn't cheap. The owners manual is pretty terrible at explaining such things as mercedes wants you to come to the dealer for everything possible in the world. I'd recommend getting a star shop manual if you are going to do any work on your car. You can get the dvd for less than $50 & that details how to do every single repair & maintenance item on the car.

dis6933

Hi

I do have the 4 DVD manual, but have not looked for this item yet.

Thanks

carguyshu

The part number for the hose that makes it quiter is 2114208826. You can get one from mymercedesparts.com for $89. Here is a thread that explains the hose & you can look to see if you have it already. My guess would be you don't.

http://www.mbclub.co.uk/forums/wheel...-solution.html