Troubleshooting car problems of rattling sound coming from brake
Car brakes are consisting of different parts that can possibly loose and can cause a rattling sound, but below is the most likely cause of sound loud enough to be notice by you when vibrates.
When a rattling sound occurs in your front disc brakes, there are two parts that are most likely causing the noise these are the anti-rattle springs and the caliper mounting bolts. The anti-rattle springs are the one that secure your car brake pads and also keep your car brake pads from rattling while the caliper mounting bolts is the one that secures the caliper to the support bracket.
Hence, if a rattling sound occurs in your rear drum brakes, the two parts that is most likely cause the rattling sound are the return springs and the retaining springs. The return springs is the one that pull the rear brake shoes back from its original position once the brakes are release (after you depressed your car brake pedal), while the retaining springs is the one that keeps the rear brake shoes properly positioned.
Possible Cause of Brake Rattling Sound
Loose brake parts
How to Fix Rattling Sound on Brake
Bring your car to a reputable auto repair shop and ask the mechanic to inspect the brake unit where you heard the sound is coming from, ask him to inspect the above items that you have diagnose that is most likely the source of the rattling sound.