brakes

hi i have upgraded the brakes on my 1980 series2 1.3 golf and i am experiencing some trouble with actually getting the pedal to go hard once pressed, most of the system is new or atleast non origional;

mk2 16v gti vented discs (brand new)
1.6 vectra b calipers
brand new pads
full brake pipes brand new
GTI servo and master cylinder
rear wheel cylinders (brand new)
new-ish shoes
brand new brake fluid

all of these have been fitted in the last month with the fluid in the system, i have blead the system so many times i have lost count, bleeding about 800ml of fluid through each nipple….so deffinantly no air in the system

once the pedal is pressed it hits the floor with minimul resistance on the way down…if you pump the pedal several times the brake lights come on but no real stopping effort….after several seconds the system completely loses pressure again and the lights go out and its back to square one again

please help me on this as it is the biggest thing left to do to my golf after 2 years of restoration…getting me really frustrated     

are you losing any fluid? Are you sure the rear brakes are adjusted right , and the servo linkage is correct?

how are you bleeding the system? as it sounds like you still ahve air in there, poss up at the MC..

Knackered M/C seals?