Noises/ squealing from the service brake in various driving situations and ambient conditions

Bulletin number

LI42.10-P-063502

Component

Service brakes

Summary

Complaint Noises/ squealing from the service brake in various driving situations and ambient conditions. Cause Frictional vibrations Remedy AMG brake systems are designed for high loads. This can result in noises under certain operating conditions and driving styles. Please refer to the Operator's Manual for further information such as care and maintenance instructions (washing vehicle directly after heavy use and using approved cleaning agents). These are dependent on speed, brake pressure or ambient conditions such as temperature and air humidity. 1. Beginning Diagnostics: a) Check whether, apart from this document, an additional document exists for the model series in question, and if so, work through it and then continue with1b. b) Check whether the complaint can be reproduced and at which axle or side the noises occur (ideally together with the customer while driving). c) Check the affected system for component wear, mechanical damage or localized overheating damage. 1. Replace damaged components as necessary and re-assess noise concern. d) Secure vehicle on a lift. 1. Start the engine and depress the brake pedal 3-4 times. 2. Check each wheel to see if they turn freely by hand. 3. If a wheel is not turning freely by hand, this needs to be addressed prior to re-assessing the noise concern. e) Assess condition of brake rotors and pads per WIS and visually (i.e. long periods of stagnation, etc...). 2. Specific Axle Work: NOTE: If brake pad has a metal backing plate, there is no need to affix the adhesive film. a) If the noises are coming from the front axle => Affix linings with adhesive film (see attachments for front axle). If backing plate is installed on pads, move to step 3. 1. Remove brake linings of front axle. 2. Clean all contact points on brake lining and brake caliper/carrier. 3. Clean bonding surface (where pistons contact back of brake pad). Apply adhesive film to the backplate of the piston-side brake lining. For 6 piston calipers, only in the area of the center piston. For other piston caliper configurations less than 6, apply where the piston(s) makes contact with the back of the pad. 4. Chamfer edges (round off sharp leading edges) on brake pads. See picture "Chamfered Pads". 5. After installing the brake linings, actuate the brake for 30 seconds. b) If the noises are coming from the rear axle => Affix linings with adhesive film and grease the lining as per the specification (see attachments for rear axle). 1. Remove brake pads of rear axle. 2. Cleaning all contact points on brake lining and brake caliper/carrier. 3. Grease contact points (red areas) between brake lining and guide of brake caliper with heat-resistant lubricating paste. 4. Clean bonding surface (where pistons contact back of brake pad). Apply adhesive film to the backplate of the piston-side brake lining. 5. Chamfer edges (round off sharp leading edges) on brake pads. See picture "Chamfered Pads". IMPORTANT: Be absolutely certain to not allow paste between friction surfaces of the pad and disc! 3. Brake Bedding Process: a) Before trip, the mileage incurred must be clarified with the customer (approx. 30 miles). b) Select a suitable route so speeds of approximately 65 MPH can be achieved. c) Brake the vehicle 15 times with a brake pressure of approx. 30 bar (have the passenger read it out using XENTRY) from 62 MPH to 30 MPH (no emergency stops and no braking in the ESP control range). Maintain a cooling distance of approx. 1 mile between brake applications. d) Finally drive approx. 3 miles to allow the system to cool. e) Reassess noise.

Owners of these vehicles have filed 116 complaints in the brakes category.