Brakes - Buzzing Noise During SBC Pressure Build Up
Date: November 15, 2007Order No.: P-B-42.46/27e
Supersedes: P-B-42.46/27d dated June 16, 2004
Group: 42
Revision History
Revision Date Purpose
e 11/15/07 Applicable Models, Content, Parts and Warranty Information Updated
d 6/16/04 Applicable Models Updated
C 12/12/03 Production Range Included and Procedure Updated
b 10/21/03 VIN Range Included
a 3/12/03 Warranty Operation Code Corrected
- 3/10/03 Initial issue
SUBJECT:
Model 211.026/056/065/070/076/082/083/087/256/265/276/282/283/287
Model 219.375/376
Model Year 2003 - 2006
Buzzing Noise During Pressure Buildup from SBC System
If you receive customer reports in the above model vehicles of a humming / buzzing drone noise during pressure buildup of the SBC system, perform the following.
Note:
The single suction damper (A000 431 04 77) is being replaced by a suction hose with integral double suction dampers.
Warning!
Work on the SBC system must be carried out by properly trained personnel. Reference WIS document S142.46-P-0001D.
1. Deactivate the SBC system with Star Diagnosis.
2. Extract the brake fluid from the reservoir completely.
3. Pull the suction hose off the SBC hydraulic unit by using a mounting wedge (W110 589 03 59 00).
Warning!
Never use a sharp-edged tool to pull off the suction hose; this can potentially damage the suction line attached to the vehicle and cause the SBC brake system to malfunction.
4. Replace the suction hose (Figure 1, A) by unfastening the hose clamp at the connection between the suction hose and suction line (Figure 2) and carefully pull the suction hose off the suction line using a mounting wedge.
Note:
Always use new hose clamps.
5. Push the new suction hose with integral dampers onto the suction line attached to the vehicle and secure it with a new hose clamp.
6. Check for leaks at the hose connections.
Note:
Even the smallest drops of brake fluid are an indication of leakage! Check suction line and connections for visible leaks after the system has been under the maximum filling pressure (2.5 - 3.0 bar) from the filling device for 5 minutes.
7. Bleed the SBC system with Star Diagnosis. Refer to WIS document AR42.10-P-0012R (211) or AR42.10-P-0012TX (219).
Special Tool
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 November 15, 2007. Please refer to Netstar --> Star TekInfo --> Star Time for the most current labor time allowance.
In Case of Warranty, use the table.