What was found
(CAN) RT BRAKE WOULD NOT RELEASE AFTER TOUCHDOWN, AIRCRAFT STOPPED ON RUNWAY, BRAKE PRESSURE HAD TO BE RELEASED BEFORE AIRCRAFT REMOVED FROM RUNWAY. RT BRAKE MASTER CYLINDER REPLACED WITH USED SERVICEABLE UNIT. OPERATION CHECK CARRIED OUT OKAY. DURING TAKEOFF THE CREW FELT A LUNGE FORWARD AFTER ROTATION. THEY FELT THE BRAKE WAS STILL DRAGGING SO THEY DECIDED TO DIVERT FROM AIRPORT . REQUESTED ERS STANDBY, ANTICIPATING POSSIBLE DIRECTIONAL CONTROL PROBLEMS AFTER TOUCHDOWN. AIRCRAFT LANDED WITHOUT INCIDENT. FURTHER INVESTIGATION REVEALED PROBLEMS WITH THE RT PARK BRAKE VALVE P/N 4500SA1. WHEN THE RT BRAKE PEDAL WAS DEPRESSED, THE PARK BRAKE VALVE HELD PRESSURE, AND WOULD NOT RELEASE THE RT BRAKE. THE PARK BRAKE