My 2000 Disco II had classic signs of leaking brake master cylinder (squishy pedal slowly moved to the floor) so I bought a new (non OEM) master cylinder and replaced it.
It works fine except after driving (stop and go) for 5-10 miles, the brake pedal will be fixed in the up position (no play) and it seems like all four wheels have the brakes applied. It's difficult to drive and the brakes start smoking and getting hot.
After it sits a while, the pedal action returns to normal.
The vendor of the new master cylinder has come up with all kinds of suggestions (but not a defective master cylinder).
I think the new master cylinder is defective.
Anyone have any ideas on anything I could check before replacing it again?
I've tried to "reseat" it (remove and retighten) but still has the problem.

 

Take your brake pads out and take it on the highway, that should clear up the blockage.

 

That's a great idea! I wonder why I didn't think of it.