Spring on front drums?
 

What are the springs wrapped around the front brake drums for? I have a noise coming from that area at low speed (30-45 mph) and it goes away above 50 mph. It sounds like it's either that spring rattling or a trim ring on the rim or something. Anybody know what it could be?

The spring is supposed to be for suppressing vibration. I was missing one on my front drum and replaced it and it made no difference whatsoever.

like 70c10 says it's supposed to reduce harmonics. brake drums can ring like a bell when they're squealing. too bad the search function isn't working cause there was a long thread on this very subject. The conclusion of the previous thread was that these springs are not necessary for normal brake function, however if a squeal developes you may notice a slight reduction in noise and embarrassment. ;)