brakes drag

Truck brakes trailer brakes or both?

 

Check the quick release valve.

 

Very nice looking 66. Did you do the paint yourself?

 

Thinking foot valve sticking but some seized clevis pins and or cam bushings could do that. Might want to put a gauge on the service side of a brake chamber and see if it is an air or mechanical problem.

 

My Truck did that when it got cold out. Had to jab the pedal hard to make them release. Happened again much colder outside. Actually brought me to a complete stop on an exit ramp. Thanks to the forum, I sprayed the foot pedal plunger with PB Blaster till I could take it apart, cleaned the cylinder and plunger/piston with 240 then 600. Coated with light amount of anti sieze. Brake pedal application was so smooth afterwards.

 

I’m willing to bet froze Clevis pins.