Another newbie from Ireland land of the midnight rain !

Hi all,
First time joining any online forums so please forgive any stupid mistakes !
I`ll add to my profile soon but am busy now the rain has stopped for a breather.
I`ve a question I hope someone can help me with.namely do I need a bigger master
cylinder as I`ve just bought some braided brake lines (the 2 full lines front to replace split front oem)
and am having a prolem setting them up,ie. one side is fine but can`t seem to get enough pressure
in the other side to get the pistons to push the pads against the disc !
Any tips or help much appreciated !
Oh yeah it`s a 94 VFR