Suspension - Groaning Noise From Front Axle
SI B37 01 11Special Suspension Systems
December 2011
Technical Service
SUBJECT
Groaning Noise from Front Axle Suspension
MODEL
F07 (Gran Turismo) with Option Code 229 (ARS) up to 2/11
F07 (Gran Turismo) xDrive models with Option Code 229 (ARS) up to 5/11
F10 (5 Series) with Option Code 229 (ARS) up to 2/11
F10 (5 Series) xDrive models with Option Code 229 (ARS) up to 5/11
F01, F02 (7 Series) with Option Code 229 (ARS) up to 2/11
F01, F02 (7 Series) xDrive models with Option Code 229 (ARS) up to 5/11
SITUATION
The customer may report a groaning or rubbing type noise from the front suspension when making a series of turns at low speeds (parking lot maneuvers). The noise may occur afier initial engine start and will dissipate as the engine reaches normal operating temperature.
CAUSE
The Active Roll Stabilization (ARS) system utilizes a hydraulic pump and an electric valve assembly Under certain driving conditions, hydraulic pulses from the pump combined with valve actuation can cause resonance in the hydraulic circuit which results in a groaning noise.
PROCEDURE
With the vehicle properly supported on a lift, inspect the ARS hydraulic lines for proper routing and any signs of damage.
Inspect the lines at the right rear in the area near the fuel tank.
Check for the presence of a rubber insulator (P/N 61 13 7 838 241) as shown in the illustration.
If no insulator is fitted, install one and then test drive the vehicle.
Please note: The noise described in this bulletin can typically be confirmed during a brief test drive within the dealership parking lot.
If an insulator is fitted, continue troubleshooting.
Unplug the electrical connector at the ARS valve block and drive the vehicle.
If the noise is still present, reconnect the ARS valve block and continue troubleshooting as the source of the noise is not related to the ARS.
If the noise has been eliminated, replace the ARS valve block according to Repair Instruction REP "3720001 Removing and installing/replacing DYNAMIC DRIVE valve block"
PARTS INFORMATION
WARRANTY INFORMATION