Bleeding brakes on dual master cly. in this order:   Right front, left front, rt rear, left rear. School master at VW school told us to do it this way. If your brakes do not improve maybe you need to look real hard at your master cly.

Yep !!! There is logic behind that.  One cly. two pistons operating independently from each other. rear stage operates rear brakes, front stage operates front brakes. If you bleed rears first, pressure is up on rears only and it will not depress front stage enough to get the air out of the front stage for hours.  Doing the fronts first, you build pressure on the front stage of the cly allowing the rear stage to "bump into" the front stage and building pressure to bleed the rears . Confused yet ?  Its kinda hard to explane without getting to tech.  Just do it that way and see if that works for you. You still may have a master cly problem. I can only assume you do not have leaks anywhere. Did you look under your floor mat where the brake line comes through the firewall ,around your pedals,along the tunnel for a rusted out line ? Check the whole line front to rear.