7/8 master is fine Mike.
Sounds like air or other such prob.........what brakes are they that your fitting ?

its the same brakes that worked before,

bluebird disc over drums on the rear and hi-lux four spots on front

i've bled four times, only other thing is bleed nipple on master, i bled this once, after just bleeding calipers didnt work, but dont know what order it was supposed to be done in or anything???

Highest point to lowest point. And as the boys say, bleed calipers with bleed nipple to the top. Sometimes you have to swap calipers side-to-side or front-to-back, so you have to bleed them with the calipers detached from the backing plates, but pushed onto the disc, so that you can keep the bleed nipple pointing up.

No Lobster..this isn't time to paste a "nipple" into the thread..

Chris

worked before and had perfect bias

Then you don't need to replace the master cylinder.

Try bleeding the M/C again. Make sure to bleed both half of the M/C, as air in either side can affect front or rear.

Generally, you bleed in this order:
Passenger rear
Driver rear
Passenger front
Driver front