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"Pumping" noise

caveman

New Member
Joined
Mar 28, 2006
Messages
23
Car
E280CDI Agarde Estate
I have recently taken delivery of an ex-demonstrator E280 CDI. As soon as I start the engine I get a sort of "pumping" noise for a few seconds which I was told was normal and was associated with the braking system. Fair enough. but I am now getting the same thing intermittently every mile or so which is quite irritating and somewhat disconcerting. It almost as though the car is having to "pump up" the brake fluid pressure to compensate for some shortfall. Is this normal?
 
SBC is a fully pressurised system so it does regularly keep itself topped up. I don't know if you have Airmatic but that system also has its own compressor which runs as and when necessary.

The noises you're hearing are almost certainly normal. After a while you don't notice them any more. :)
 
caveman said:
I have recently taken delivery of an ex-demonstrator E280 CDI. As soon as I start the engine I get a sort of "pumping" noise for a few seconds which I was told was normal and was associated with the braking system. Fair enough. but I am now getting the same thing intermittently every mile or so which is quite irritating and somewhat disconcerting. It almost as though the car is having to "pump up" the brake fluid pressure to compensate for some shortfall. Is this normal?

Hi Caveman, I'm getting the same irritating noise (and vibrations) from my E240 which comes derives from the SBC and so are are others as I found out through recent correspondence on this site although Mercedes are saying this is normal. It spoils a great car.

Pete
 
Sorry to say that is what SBC sounds like. Should not be so but there it is. Blame Bosch who sold it to MB along with promises of wonderful things

I understand there is a damping kit available that reduces the vibration in the system but you will never get away from the fact there is a pump doing some, er, pretty heavy pumping!

I do not notice it much other than at start up. It is there in traffic but like many domestic and motoring noises if you worry about it too much and start listening out, it becomes a big problem. There is a limit to what can be done.

SBC Stop is another good idea on paper. My theory is that many people engage it by accident in traffic because they hit the Cruise Control stalk rather than the indicator. Easily done.

It works well enough but never quite confident enough to do anything then keep my foot hovering over the brake pedal which defeats the object really.
 
caveman said:
I have recently taken delivery of an ex-demonstrator E280 CDI. As soon as I start the engine I get a sort of "pumping" noise for a few seconds which I was told was normal and was associated with the braking system. Fair enough. but I am now getting the same thing intermittently every mile or so which is quite irritating and somewhat disconcerting. It almost as though the car is having to "pump up" the brake fluid pressure to compensate for some shortfall. Is this normal?

There is a silencing valve kit which may address the issue. It should be done under warranty regardless of age as it is a design flaw not a design feature. Anyone who states that it is part of the system (re Benz Mechanics) is trying to save themselves the paperwork on an ex gratia warranty application.
 
I have read lots of threads about the "pulsation damper" kit being fitterd under warranty, but these seem to date back to 2004 models or even earlier. Is it really true that cars registered as recently as Nov 2005 may still have not been fitted with the necessary modification from new?!
 
caveman said:
I have read lots of threads about the "pulsation damper" kit being fitterd under warranty, but these seem to date back to 2004 models or even earlier. Is it really true that cars registered as recently as Nov 2005 may still have not been fitted with the necessary modification from new?!

I think we all agree that the sound is not meant to be there. So it just depends on what is really going on.
 

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