Rubber boot
 

Hi there. First time posting. We bought a used Sebring in October and we already had to replace the front brakes and roto.....however we wanted to know the purpose of the rubber boot that was around the caliper bolts? Obviously since it was a long long time ago when the brakes were last replaced, the bolts were very rusted and well the rubber boots had to be picked apart which made them fall apart. Just curious what their role is since we replaced everything back to normal minus the boots.

Thanks

dust covers so crap does not wear off the grease that allows the slid pins to move freely.