Brakes

Rubber hose if equipped may be falling apart on the inside even though outside looks good. But I suspect the master cylinder, some of these models have some valves attached close to master and some models closer to the lower side of firewall (Splitters) and I do not know which you have these too can get plugged by the loose parts from bad brake lines. But if valves are attached close to the master if buying a new master it is my understanding that at least from some suppliers they come with the splitter valves while re-manufactured units do not. It could be just the master and a reman will be fine for you but it may also be those valves and/or the rubber lines from steel lines down to the calipars. Sometimes the master can even slowly be applying pressure on its own and ends up getting very hot, the whole brake assy and wheel too then it sticks to disc in short burst until the force of driving gets it to let loose or it could be particles in the lines that made its way to the splitter valves and master.