problem with brakes grabbing and not releasing

[djhurd09]

Ok so i just bought this truck its a early 99 f250. I knew it had brake issues when i bought the truck. I drove it around for a few days with no problems but to day when i went to go buy oil and filters for it the brakes begun to start dragging and not release. I believe i need to replace the hydro boost on it. has any body else had this problem. any info would be great! thanks