Land Rover Repair: disco 11 brake question, lake ariel, clevis pin

Question
hi john. john here from j & j auto in lake ariel pa. have a 2001 disco that my wife drives.once in a while , although more frequently recently, all 4 brakes apply without any pressure applied to the pedal.she doesnt notice until they start to get hot, she puuls over, shuts the truck off, waits ,starts it back up and away down the road it goes.we had this problem once before with an older audi 5000 that blew a n abs fuse and applied the brakes. being amechanic i wouldnt have beleived this if i didnt see it.based on that experience, to try to narrow the disco problem down,we unplugged the abs to try to eliminate it as a possibility.she drove home and called me and told me it did it again.having a knowledge of cars i cant imagine what cuold make the truck apply the brakes on its own. i did see some mention on a forum about a worn clevis pin causing a binding of the pedal to servo linkage. it this what i should be checking? any other suggestions?any help will really be appreciated so i can resolve this without pulling my hair out , thanks in advance , john

Answer
I have only seen a few cases of Land Rovers doing this with all four wheels and each time it was the complete modulator assembly - the $2000 part - that cured the problem.  A mechanical problem like you suggested would leave the brake lights on all the time as the linkage dragged.  That's not happening is it?

When one wheel drags it's usually a caliper or hose.