I may have already put this info on here somewhere, but if not and you wind up with an overhauled modulator and new accumulator pushing a problem down to the brake pump, it's an easy fix.
The pump started leaking and on stripping down, found an o-ring past it's best. This is 50mm I/d, 2mm X-section.
Of course, replacing this caused another leak. The shaft seal on the motor. Any pump shop should be able to supply (they're used on thousands of domestic water pumps here) and is called by the catchy name of , 16x8x6, SC/SF, NBR, SOG.
It's been three years or so now since I did all the brake works and not had a jot of trouble. Topped up the fluid once, not long after completion and never since.
Must be due a fluid change now!
Hope the above info helps.