Brake problems with 1994 Nissan Pickup 2WD?

My truck brakes locked up last weekend, since then I replaced the Calipers, and pads. it's still locking up on the driver side. Does anybody know what the problem may be or a website that I could use to diagnose the problem? Here are the possibilities I have been told. The new caliper is bad, the brake line is deteriorating or kinked. I checked that and I know it isn't kinked, it may be deteriorating. I have been told it may be the increase cylinder or the master cylinder went bad. This truck has 247,000 + miles on it.

dirt in the brake system will because this to happen,when the liquid gets contaminates in it, it causes the calipers to stick on it,this will because the problem your having,i own a shop and I get one of these every week like this,some Chevy's,other different makes also,it do not mater what kind of car it's,dirt will because this to happen,you can totally flush the system out on it and maybe stop it from doing this,you may have also got a bad caliper,this happens lots,because all of the replacements are rebuilt,and anything can go wrong with them,you,ll have to start by bleeding the system and see if that assists it,good luck with it.

been a certified mechanic for 37 yrs.

If the lines to the caliper appear like a rubber hose and I assume that it's then the hose part of the line collapsed on the inside and clogged up. If you replace this hose it'll fix the problem. Been there and done that.

there is a valve in your brake line that sends the brake liquid off to the individual wheels, its name escapes me now, but from what you're reporting, it sounds like that valve either went, or is sticking. if you get that valve unit replaced it should take care of everything for you. Best recommendation's with that's to take it to a brake shop because of how broad the work is.