There isn't a recommended procedure, but this is what I do: Change the brake fluid every year, especially on the pump side of the reservoir ( the engine side). If the fluid is so dirty that you can't see the bottom of the reservoir, you're long overdue for a change. Get a turkey baster and suck the fluid out and then wipe that griity, pastey stuff out. This is the stuff that gets into the check valve and clogs it. Refill the reservoir with fresh fluid. Drive the car a few weeks and do it again. This should get most of the fluid changed. Do the same on the outboard side and open the bleeders and let them drip until clear fluid comes out. Remember, this is *my* recommended maintenance and is what I do.
Mark