So my rear passenger side break is locked up. When I got home from work today I noticed my 1990 pickup was driving slugish and could smell the break pad burning, when i got outside my truck i could feel intense heat radiating from that wheel. When I reverse there is a loud clanking sound, I already did the obvious and took apart the breaks for a good cleaning, it helped with the locking for like a mile then it went back. Any ideas?

 

seized wheel cylinder. often times they will break loose for you, but then freeze back up at any given time, but most likely minitues after they un-freeze they freeze back up

 

That, OR you have had the brakes out & put the adjusters back on the wrong side...

 

bad shoe return springs, out of adjustment parking brake.