1972 front Dunlop calipers

[Puffdaddy#1]

Having a problem with brakes dragging ,and not retracting.I have had no previous issues,pads are like new.

The fluid does look strange,was fine last time I checked but now front resivour is clear but darkish,and the rear looks to be not clear and a light brownish.

Retracted the pads using my c clamp put the caliper back on ,pushed the pedal only inside piston moves ,buy the way only having trouble on driver's side.

What's your opinions or options,can I rebuild these originals, flush and change fluids and lines?