Suspension - Front End Cracking/Grunting Noises On Bumps

CRACKING/GRUNTING NOISES FROM AREA OF FRONT AXLE WHEN DRIVING OVER LARGE ROAD UNDULATIONS

Topic Number LI32.35-P-047253

Version 1

Design Group 32.35 Stabilizer

Date 07-07-2009

Validity MODEL series 221 with SA code 489 (Air suspension)

Reason for change Supercedes DTB P-B-32.20/47C

Reason for block

Complaint:

Cracking/grunting noises from the area of the front axle when driving over speed humps or large road undulations.

Cause:

Relative movement of torsion bar mount in bracket.

Remedy:

Check: Detach torsion bar from torsion bar linkage and drive the vehicle.

If the complaint no longer occurs, bond the torsion bar mount in its mounting/bracket. Otherwise look for another cause.

Please prepare the individual steps throughly as the repair must proceed without incident.

The adhesive must be mixed and applied, and the torsion bar bolted, within 5 min otherwise a successful repair cannot be guaranteed.

Two persons are necessary to carry out the repair.

NOTE:
Only use adhesive A005 989 0971 (Figure 1)

1. Detach torsion bar from torsion bar linkage and remove torsion bar mounting clamps.

2. Roughen up torsion bar mount using emery paper (Figure 2)

3. Roughen up torsion bar mount shell using emery paper (Figure 3)

4. Roughen up counterpart of torsion bar mount in frame-type integral support using emery paper (Figure 4)

5. Clean roughened surfaces with nitro thinner, brake cleaner or similar (Figure 5)

6. Squeeze all the component adhesive out of the tubes and mix throughly. Use up all the adhesive (Figure 6)

7. Apply adhesive evenly to torsion bar mount, torsion bar mount shell and recesses in frame-type integral support. (Figure 7, Figure 8, Figure 9)

8. Within 5 min bolt the torsion bar onto frame-type integral support (tightening torque 70 Nm) and remove excess adhesive (Figure 10)

9. Remove vehicle from vehicle lift and allow adhesive to cure for 1h.

The torsion bar must not be bolted to the torsion bar linkage.

10. The adhesive is cured after 1h. Now bolt the torsion bar linkage to the torsion bar.





Attachments








Symptoms





Parts





Work units





Validity





Attachment - (Figure 1) 2-component adhesive





Attachment - (Figure 2) Roughen up torsion bar mount





Attachment - (Figure 3) Roughen up torsion bar mount shell





Attachment - (Figure 4) Roughen up frame-type integral support





Attachment - (Figure 5) Clean the components





Attachment - (Figure 6) Mix adhesive throughly





Attachment - (Figure 7) Apply adhesive evenly to torsion bar mount





Attachment - (Figure 8) Apply adhesive evenly to torsion bar mount shell





Attachment - (Figure 9) Apply adhesive evenly to frame-type integral support





Attachment - (Figure 10) Scrape off excess adhesive