Can Someone Help Me:
I have a 10 month old BMW 530 Sedan (E60) with the Dynamic Drive + Active Steering options. The Dynamic Drive functions magnificantly as far as limiting body roll is concerned. However, when the power steering pump fluid is warmed up, the rear Dynamic Drive actuator on the rear anti-roll bar generates a "hollow, hydraulic stick-slip noise" when you corner very slowly left or right above a speed of about 10 kph. Also, when the car is pulled up to a stop (and the body has stabilized) a clicking noise (again like "hydraulic stick-slip") is emitted from the rear Dynamic Drive actuator for about 0.5 seconds. The noise is definitely not a mechanical noise generated by the rubber bushes stick-slipping etc.. The noise has energy associated with it and seems, to me at least, to relate to the Dynamic Drive actuator. The noise only occurs once the steering hydraulic fuild has warmed up - the Dynamic Drive hydraulic circuit is driven by the power steering pump. I believe it's a tandem vane pump, one vane set generating flow for the power steering circuit and the other vane set generating flow for the Dynamic drive system. Can anyone help please?!? I had the problem looked at by the BMW dealer who sold me the car - and he says the noise is "normal". What a joke. As an automotive steering engineer I certainly believe the noise is not "normal".