Disc Brakes

[CudaJon]

Rather fundamental question (I think well I hope). 

My front brakes on my 73 Cuda are disc.  So when I take the tire off on either side and spin the rotor by hand it does not move freely. That is, it rubs against the caliper. I can still rotate it  (I been driving the car like this) but clearly its rubbing.  My question is: Where is the problem (rotor, caliper, something else) and how do I fix this if it is a problem?  Thanks for reading!!

[MoparCarGuy]

Master Power Brakes troubleshooting checklist https://techtalk.mpbrakes.com/how-to-series/how-to-diagnose-fix-brake-drag

[Chryco Psycho]

Pictures would help , must be mismatched parts

[MoparLeo]

Have to see what you are dealing with. Many things can cause the brakes to drag.
Sticking caliper slide, sticking caliper piston lip seal, restriction in brake hose holding pressure and more.

https://www.freeasestudyguides.com/brake-piston-seal.html

[Rich G.]

You can start by cracking  the bleeder screw open and see if the wheel loosens up. If it doesn't free up it's in the caliper or slide. They will have a slight drag anyway.

[Filthy Filbert]

can you better describe or maybe make a video?   

there should always be SOME drag on the brakes, regardless if disc or drum.   With the wheel and tire on, the front wheel should spin 1 to 1.5 times when you try to spin it by hand.   Maybe less in the rear due to resistance from the differential, driveshaft, transmission internals, etc.

Drums are to be adjusted so the shoes are right up against and just slightly dragging, this eliminates a soft spongy pedal or having to "double pump" the pedal to stop.

Discs do not have retraction springs, so when the piston is pushed out, it will stay up against the disc, just with no pressure behind it. 

Do you have one wheel that's hotter than the rest after normal driving?   are ANY of the wheels hot after normal driving with no hard stops?   

[MKA]

 

1 to 1.5 turns sounds right.  When I had a sticking caliper one wheel would turn half turn and when I used the handheld temperature gauge it ran over 200 degrees hot on the hub.  Not good for the bearings.  The other wheel would turn 2 turns and 125ish on temp.   Change caliper, both wheels are now back within a reasonable range of each other.  Comparing your wheels, tracking ur free turns and temp is a good idea. 

[CudaJon]

Thank you all for responding.  I will make a quick video with some detail - my bad.  Weather here is turning for the worst. Today 60, tomorrow 20 with snow, so I will get something out in a couple of weeks hopefully.  Thanks again everyone!!