Technical Dragging brakes

Ok folks an issue I'd like to resolve.
disc fronts and drums rear.
Booster and dual port master.
All corners are dragging badly and then the drums stay energized and brake lights stay on. and getting the whole set up really hot.
Where do I start? Residual valves, master, pushrod seems to be adjusted correctly.
Thinking it could even be the fluid heating up even though there seems to be enough air flow between all the components

 

"pushrod seems to be adjusted correctly"


you also need to know if the rod between the master and booster is adjusted with some freeplay. Often overlooked, but with all 4 getting hot, I'd start there.

 

Yep, what he said.

 

X2..if brake lights are staying on and they are activated by a pressure switch good clue that MC piston not returning all the way..

 

Measured it all and the pushrod is correct...residual valves next try or could it somehow be a faulty booster/master?

 

I suppose I'd next try to see if there is any pressure at both MC line fittings?

 

Loosen a line and see if it has pressure on it. If so, take the mc off and check it out.