[mike16]

take picture, somebody already did but take lots of pictures.

there is a piston inside the distributor block located just below the master cylinder. when one side of the system fails that piston moves over and blocks the flow of fluid so no more than an absolute minimum is pumped out.

that piston needs to be re centered and held in the center position while both front and rear brake systems are flushed

fix that and flush the whole system, front and rear, befor removing the master cylinder or any wheel cylinder

If you dont.. you will be pumping old dirty fluid into your newly rebuilt wheel cylinders.

flush the system first, then take off various components, one at a time , rebuild it reinstall it before going on to the next component. Always think in terms of NOT pumping dirty fluid into your clean newly overhauled system.