Interior - Vibration or Buzz Felt in Steering Wheel
Group 32Steering and
Wheel Alignment
Bulletin Number
32 O3 97
Woodcliff Lake, NJ
May 1998
Product Engineering
This Service Information bulletin supersedes S.I. 32 03 97 dated October 1997 which should be removed and discarded from your S. I. binder.
The models affected have been expanded to include the 323i
SUBJECT:
Vibration or Buzz Felt in Steering Wheel
MODEL:
328i, 323i
Situation:
Some 328 and 323 owners may complain of a high frequency "buzz" felt in the steering wheel at a particular engine speed, and in some cases a vibration resembling a tire balance problem felt only in a two to five mile per hour window, usually in the 50 to 60 mph range.
This can be caused by hydraulic pulses set up by the power steering pump used with the M52 engine that are transmitted to the steering column through the steering rack.
A kit to stiffen the steering pump mount and to dampen hydraulic pulses in the system has been developed for cars that exhibit this condition.
In case of customer complaint, determine if what the customer describes as a "wheel shimmy" is actually being caused by the hydraulic system, by driving the car to isolate the speed at which the vibration occurs. Drive at a speed higher than the critical speed, drop the transmission into neutral, and allow the car to coast through the critical speed with the engine at idle. If the vibration is now gone, the kit should be installed.
Note:
This repair does not apply to the 552 B32 engine used in the M3, or to the Z3.
Procedure:
Disconnect the pressure line from the pump and allow the fluid to drain into a pan. Disconnect the pressure line from the rack and remove the line
Remove the M6 bolt (2) that holds the cooling tubes to the right side of the rack, and hang the new line (1) using the new M6xi 6 hex bolt. Tighten to 9 Nm
Connect the pressure line (1) to the pump and rack using new seal rings (D) and tighten to 35 Nm. Make sure there is adequate clearance between the line and other components
Remove the two T4O bolts from the back of the pump.
Install new brace (1) to rear of pump with new M8x5O bolts (3) and washers. The small portion of the brace will line up with two tapped bosses on the block. Use two M8x22 bolts w/washers (2) to fasten the brace to the block. Tighten to 24 Nm.
Note:
The illustration is with the alternator removed only to show the position of the bracket. It is not necessary to remove the alternator for this repair.
Remove the mounting bracket from the fluid reservoir, and save the M6 clamp bolt (1)
Push the rubber grommets (1) into the mounting holes of the new bracket, and push the spacers (2) into the grommets. Mount the bracket to the car with new bolts (4) and washers (3), and tighten to 24 Nm. Tighten clamp bolt (5) to 5 Nm. Top off and bleed system, test drive.
Parts Information:
This repair requires the parts as shown.
Warranty Status:
Covered under the terms of the BMW new car limited warranty.