Not being there..here is a stab...first follow the directions as I am thinking that this will hold the porportioning valve center. It will slip to block if you should have a failure (open line, have seen this while bleeding). Sometimes these vlaves get off center and I am sure you don't have the alrm light hooked up indication this condition, test to ground with ohm meter) Another method of centering as was directed by ford years ago when I worked for them..(Mopar never broke so you starved to death) first stomp the brake very severely, it may seat the valve center...their method was to bleed with the power on..watch the light..bleed a rear..if light did not flash, bleed the front till you cross over with a flash or go out and stays out..if did not extinguish and did flash..then very carefully go back to other side and open with light pressure till you observe the light go off..lock her down..this will require the light hooked up and another warm body.