Is your master cylinder the same as this one ?
If so, the 2 ports visible at the front go to the front brakes ( 1 port per front wheel )
The rear single port ( Hidden from view in the picture ) goes to the rear wheels & is normally split with a T piece at the rear end of the car.
Don't know if you are using a new master cylinder, if not, it is not uncommon for the internal seals to fail after a prolonged period of storage
I chose to alter the angle of my master cylinder so as the fluid reservoir would sit a bit more level & as an aid to help prevent airlocks in the cylinder.
If you are unable to get any brake fluid moving, I would look towards the master cylinder first.
Seem to remember that AshG had a faulty master cylinder & that was a brand new unit.
Perhaps this is of some help to you
