drum brake problem?

if its the one in your sig try taking off the hub and have a look at the shoe. i would take it off and clean everything real well and reinstall the shoe..have you tried to tighten the brake with the wing nut first? the shoe could be worn a little and needs to be tighten up more
 
Your sig states +04 hydros

If it was the pads worn out you would hear it, or it could tend to grab.

Could the piston be binding.