This TSB applies to 2007 BMW Z4 models produced up to October 2006. A creaking noise may be heard from the center area of the instrument panel while driving over rough roads. In some instances the noise appears to be coming from the engine compartment.
The likely cause: One or both of the fasteners which secure the strut bars to the bracket on each strut tower has loosened, or one or both of the strut bar brackets has fractured and separated from the strut tower.
Re-torque the fasteners securing the strut bars to the brackets. If necessary, replace the mounting bracket(s).
For vehicle produced up to May 2006, torque the M10 nut securing the strut bar to the bracket to 41 Nm. For vehicles produced from May 2006, replace the M10 bolts (P/N 07 11 9 906 010) that secure the strut bar to the brackets. Note that the tightening value for these replacement bolts is 56 Nm plus an angle of 105 degrees (+/1 15 degrees).
If the brackets are fractured and must be replaced, remove the suspension strut on the damaged side(s). Drill open the weld points on the fractured bracket. Remove all remaining pieces of the damaged bracket from the strut tower. Using the drilled open weld points as a mark, use an 8 mm drill bit to drill, for plug welding the new bracket to the strut tower. The new bracket (P/N 41 00 7 193 040) differs from the brackets that were installed up to May 2006 (a weld nut is featured as opposed to a welded bolt). Loosely connect the strut bar to the new bracket using the new bolt and center the bolt in the elongated hole of the strut bar. Use the outlines of the old bracket on the strut tower to align the new bracket.
Secure the strut bar bracket to the strut tower by plug welding.
Clean the repair area as needed. Refinish the surface on the outside of the strut tower to prevent corrosion. Coat the inside of the strut tower with primer, followed by undercoating.
Tighten the strut bar to the bulkhead mount and tighten the bolt securing the strut bar to the new bracket (using torque-plus-angle tightening of 56 Nm plus 105 degrees).