Brake Issues

I have a 1993 Nissan Pickup 4WD and my brakes keep locking up. I've changed the master cylinder and bled the brakes twice on all four tires and you can drive it for a little while then they lock up again. I have to pull over and set for awhile and then the brakes will eventually let up and then I can drive it home. Does anyone have any suggestions?

just did the brakes on my truck. front and back. replaced everything and my passenger rear tire kept locking up. it could be ur shoes are real thin and r way adjusted out causing your wheel cylinder to stick. i put new shoes and drums and still had to turn my drums 30 thousands over so the wheel wouldnt lock up