Quote:
Originally Posted by XavVD
From my understanding, parking brakes generally use the rear caliper but activate them mechanically and not hydraulically. Then how the noise potentially occurs, no clear idea but I would suspect that caliper can get a bit of free play that generates some squeal noise (under low force braking) and after a few braking actions caliper has absorbed this free play (centering of shim in a pin/piston, shim getting perfectly perpendicular to pin/piston ???). Perhaps as parking brake is applied mechanically (in parallel to normal hydraulic brake system) force to caliper is applied at different location and not perfectly in uniform way that generates some shim slanting that is corrected after a few brake actions. Any brake specialist to confirm???
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On BMWs the parking brake is usually a drum brake integrated in the rear brake rotor. It is a completely separate system from the regular brakes.