M5 and M6 Front Axle Brake Squeak with Compound Brake System. A squeaking noise can be heard when braking from a slow speed. This situation may apply to M5 and M6 vehicles fitted with the metallic brake pads (P/N 34 11 2 284 869). These pads can be identified by the absorber weights at the top and bottom. Due to the design of the fixed caliper brake system, an unfavorable interaction between components may cause a squeaking noise.