Suspension - Front End Knock/Thump On Bumps
Date: September 4, 2008Order No.: P-B-33.15/12d
Supersedes: P-B-33.15/12c dated May 25, 2007
Group: 33
Revision History
Revision Date Purpose
d 9/4/08 Applicable Models (230.470 included), Parts and Warranty Information Updated
c 5/25/07 Warranty Information (Cause 2) Updated
b 5/10/07 Applicable Models, Parts and Warranty Information Updated
a 2/9/06 Applicable Models, Process and Warranty Information Updated
- 9/14/04 Initial issue
SUBJECT:
Model 215.373/374/375/376/378/379
Model 220.067/170/173/174/175/176/178/179
Model 230.470/471/472/474/475/476/477/479
Knocking or Thumping Noises from the Area of the Front Axle While Driving Over Rough or Uneven Road Surfaces
If you receive customer reports in the above model vehicles of knocking noises from the area of the front axle as described above, please consider the following possible causes as part of your diagnostic routine.
Cause 1: Rubber mount on spring control arm cracked.
Remedy 1: (Damage Code 33126 36)
1. Perform visual inspection of spring control arm rubber mount.
2. If rubber mount is cracked continue with steps 3 through 7 (Figure 1 and 2).
3. Remove spring control arm. Refer to WIS document AR33.15-P-0170I.
4. Remove/install/replace spring control arm bearing (spring control arm removed). Refer to WIS document AR33.15-P-0170-02I.
Note:
Replace the spring link bearing in pairs. If the bearing failure results in the lower control arm grinding in to the pick-up points of the front sub-frame, the front sub-frame must also be replaced. At this time if it is determined that there are any additional components in need of replacement due to causes two and three below, that they are to be replaced with no additional labor charges at the time the vehicle is disassembled.
5. Press out/in using tool W220 589 06 43 00. If there are visible signs of grinding on the pick up point of the front sub-frame (as a result of a complete control arm bearing separation), the front sub-frame must be replaced.
6. Remove/install/replace front axle sub-frame. Refer to WIS document AR33.10-P-0100N (215), AR33.10-P-0100I (220) or AR33.10-P-0100R (230).
Note:
Wheel alignment is included in the repair of the subframe.
7. Install spring control arm. Refer to WIS document AR33.15-P-0170I.
Cause 2: Sealing bellows of supporting joint damaged, resulting in play in supporting joint.
Remedy 2 (Damage Code 33113 D1)
1. Check sealing bellows and play at supporting joint.
2. If there is visible damage and/or noticeable excess play, continue with step 3.
3. Remove/install/replace supporting joint. Refer to WIS document AR33.20-P-0440I
Cause 3: Torque strut joint may be worn and/or the rubber mount of torque strut cracked.
Remedy 3: (Damage Code 33140 36)
1. Check play of torque strut joint and visually inspect the condition of the rubber mount. Only replace torque strut if rubber mount is visibly damaged. After check play, remove/install/replace torque strut. Refer to WIS document AR33.15-P-0160I.
2. Lift vehicle, wheels must be relieved of load.
3. Move torque strut vertically up and down near the ball joint.
4. If there is perceptible play, remove/install/replace torque strut. Refer to WIS document AR33.15-P-0160I
5. The torque strut can only be renewed for one of the two causes not both.
6. No wheel alignment is required for this procedure.
Parts Information
Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on September 4, 2008. Please refer to Netstar --> Star TekInfo --> Star Time for the most current labor time allowance.
In Case of Warranty, use the table.