If the pedal is extremely hard to push I would say check the vac line to the booster and the booster itself. If the brakes are locking up and sticking is it the front or rears? My wife's 86 Runner had a problem with the rear drums being so rusted the ebrake "arms" on the axle housing would not spring back when you released the parking break and the ass end would be locked up until you gave it Gas and popped the brakes loose a bit. Needless to say she has all new brakes now.
Nate