Brakes - Squealing Noise
46 08 152017130/3
December 16, 2008.
Supersedes Technical Service Bulletin Group 46 number 08-03 dated April 3, 2008 for reasons listed below.
Affected Vehicles
46 Brakes squeal
Condition
Complaints of brake squeal.
Technical Background
Production Solution
Not applicable.
Service
NOTE: Before proceeding with any of the following steps, check the overall condition of the brakes. Verify that the brake discs and brake pads, which will be serviced according to the following procedure, will not reach their wear limit as a result of this procedure.
WARNING: Never use compressed air to clean brake dust from a brake system.
The following procedure has proven effective in reducing brake squeal and may be used for both front and rear disc brake systems.
Brake disc, cleaning
1. With the wheels removed, mark the position of each brake disc in relation to the hub so that the brake discs can be reinstalled in the same position. Work on one brake at a time to avoid mixing up parts.
2. Using a power disc-type sander with an 80 grit sanding disc, clean both sides of the removed brake disc.
Figure 1:
3. This should result in a crosshatch pattern (Figure 1).
Figure 2:
4. Lightly sand the brake disc in a clockwise direction using the leading edge of the sanding disc.
Then continue sanding in a clockwise direction using the trailing edge of the sanding disc.
Brake pad, cleaning
1. Some front/rear brake pads may have an adhesive (sticky) backing, which helps adhere the brake pad to the brake caliper. If the vehicle is equipped with this type of a pad, remove this sticky backing and any residual adhesive from the baking plate of the brake pad and brake caliper. Some front/rear brake pads have an anti-vibration backing plate (non-sticky). Do not remove this type of backing.
Figure 3:
2. Clean face of the brake pad with sand paper.
Figure 4:
3. Slightly chamfer edges of brake pads with a file.
Brake caliper, cleaning
NOTE: The following steps require a thin coat of Plastilube Moly3(R) high temperature grease to be applied to various parts of the brakes. This grease must never come in contact with the braking surface of the brake pads or brake discs.
Figure 5:
Figure 6:
1. Thoroughly clean all contact points (Figure 6) where the brake pad backing plate makes contact with the brake caliper and/or the brake carrier.
Reassembly
1. Reinstall brake discs in their original position. (See Brake disc, cleaning, Step 1.)
2. Prior to reinstalling the brake pads, apply a thin coat of Plastilube Moly3(R) high temperature grease to all contact points (Figure 6) where the brake pad backing plate makes contact with the brake caliper and/or the brake carrier.
3. For brake pads that have springs (common on rear brake pads), apply a thin coat of Plastilube Moly3(R) high temperature grease to the springs where they make contact with the brake caliper.
Warranty
When procedure applies to vehicles under warranty, use the table.
Required Parts and Tools
Part Number Part Description
ZVP 264 103 Plastilube Moly3(R)
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.