Dogshine

for me, it seems as if the pump is turning on more often now than in the past.... recharging after three or four depressions of the pedal. Is this the same as on others cars?

In the garage without the engine running, the sbc pump will reprime after every three depressions.

komp55

The SBC control unit "wakes up" and applies hydraulic pressure to the caliper pistons upon the occurence of any of the following events:

1) opening a door on the car;
2) operating the central locking system;
3) depressing the brake pedal (once);
4) turning the key to position 1; and
5) operating the parking brake.

izzyz28

That's about what mine does. I'm not sure what the threshold pressure for the accumulator to recharge is, but I can certainly see three or four depressions being enough to lower the pressure significantly.

stevebez

It cycles very often - mostly to check if its faulty... paranoid MB techs ... although they have failed before! One of my biggest worries with the car.

MB "officially" said they were discontinuing it in the E class as the system was too expensive for that vehicle line.

SLR and Maybachs still use it (dual systems I think) so I suppose it can't be too bad.

Dogshine

wow - so many people here with sbc and nobody knows the answer to this question.

if our sbc is going bad, nobody knows what is normal. Yesterday for me it seemed that for every three depressions of the pedal, the pump would re-prime itself. is that the same for everyone here?

in addition, the vibration in the pedal could be less with a 'pulsation dampener' installed and I plan on getting that done on my next trip to the dealer.

how many depressions of the pedal require your SBC pump to re-prime?????