wow, sounds almost exactly what i have been dealing with. it appears that the length of the push rod is quite critical.
being away from working on autos for 25+ years, i had long forgotten everything that i once knew about braking systems so i found the following website to be of great help (please forgive my transgression in looking at a honda website, i promise to do penance) specifically at the end of part 5 is a description of what may well be occuring to cause the brake lock-up. to aid in understanding, the article has very descriptive diagrams of what occurs in the master during a braking cycle.
hope it helps.
nazgul
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