I'd want to make sure its actually a brake issue and not a bearing issue.  Pull the wheels and the calipers and see if the rotors spin freely.  If so then its the brakes.  If not then check those bearings pronto because something is bad wrong. 

Gaba wrote:

65 mustang
Kelsey hayes 4 piston front brake setup, drum rear
MS brake booster and pedal assembly setup
Dual master, proportioning valve,  the whole shabang required to make it work right

While the car is in the air for a transmission change out, noticed that the front tires are hard to move. Not crazy hard but hard enough to not spin freely.. ? Will post a video too.. soon.. but till then, what could be the issue ?

The K-H 4-piston calipers can and do rust shut.  The fix is to disassemble the calipers, free all 4 pistons, then sand out the rust with emory cloth & rust remover.  Rebuild with new rubber/neoprene parts that comes in a kit.  Or...Go to Stainless Steel Brake Co and get new calipers.  They have stainless steel inserts in the bores and will never rust again. the calipers have only two bolts, so they are easy to separate.  The Mustang Shop Manual has a good description of the rebuild steps.

Sounds easy, but it may not be that easy.  My first try took about 6 hours for one piston!  The neoprene sealing rings can also glue themselves to both piston and bore, adding to the problem.  Yours does not sound that bad.  Get a piston removal tool - SSBC has them or you might try your local good parts store.  try to not scratch up the pistons as they are very expensive to replace.

There are two different types of dust covers used to seal the pistons from dirt, etc.  In 67 they changed the design and it is not compatible with the earlier version.
 

 

Disc brake will drag slightly as there is nothing to return the pistons. Back in the 60’s and 70’s many drag racers would use front drums for this reason. With the drums they could slightly back off on adjustment so there would be no drag. Another possibility is either the master cylinder has a residual check valve and you’re plumbed wrong or there is a remote residual check valve somewhere. Definitely check for rusted pistons in the caliper too, that would be the first thing to check.

Gaba wrote:

https://youtu.be/qGytN2n7JMM


Here is a video

Car has been running , discs are fully functional , installed 2 years ago

 Looks normal to me.