Master Cylinder
Remove the brake line from the master cylinder and place your finger over the end of the master. see if you can build pressure on your finger. If you build pressure on your finger you should try and bench bleed the master cylinder.
Where you removed the brake line from the master cylinder, try and find a plastic fitting that will fit in that hole. Make sure your fitting has a barb on the other end as you will be installing a short piece of plastic clear line onto this fitting. Place the other end of the plastic line back into the open top of the master cylinder.
Pump the brake lever and take note if your see and fluid moving in the line. If your see no fluid moving or no pressure on your finger, the piston in the master will have air in it or the seals in the master cylinder have failed. Some brake system are hard to bleed the air out.
Try and use only a plastic fitting as this is a banjo fitting, a pipe thread in plastic will not damage the master cylinder.
CAUTION NOTE BRAKE FLUID WILL REMOVE PAINT FROM YOU MACHINE TAKE CARE NOT TO LET IT SIT ON ANY PART IF IT SPLASHES ON IT.