front driver side brakes locking up??

sometimes when i am driveing my front driver side brakes don't lock up but rub on the disks?? i am pretty sure they are not warped and this doesn't happen all the time?? i was wondering if anyone would know y this would happen??

stoney

sounds like a bad caliper or bad/ blocked up brake hose or the pins that let the caliper slide back and forth are sticking. Any of those things could cause that problem. $0.02