Are these original brakes or aftermarket brakes?

Spike
1965 Ford Mustang fastback 2+2 A Code 289 C4 Trac-Lok
Vintage Burgundy w/Black Standard Interior; Vintage 40
16" rims w/BF Goodrich Comp T/A gForce Radial
225/50ZR16 KDWS skins; surround sound audio-video.

"When the time comes to lay down my life for my country,
I do not cower from this responsibility. I welcome it."
                                -JFK Inaugural Address

You should have a combination valve located on the frame
below the master cylinder.  It controls proportioning,
failure warning and distribution.  They were bad about
freezing if the fluid was not periodically flushed.  Another
problem is the valve needs to be centered after the brakes
are flushed or bleed.  Do you have a light on the dash
illuminated?  If so your job to center the valve and retrun
flow is simple.  You need to have someone gently apply the
brakes while you have a bleeder valve open until the light
goes out.  Immediately stop applying the brake and close the
valve.  If you cann put the light out by doing this on one
end of the car, go to the other end and try it.  Usually,
the las bleeder you opened will cause the valve to close off
that system as it should.  The idea is to go bach to the
other end of the car and open a bleeder whil cracking the
bleeder to center it again.  That will restore fluid
pressure to all wheels in most cases.

Good luck
Lugnut