Bronco, "E" & "F" Series

To check master cylinder for internal leak, fill reservoir as necessary. If fluid level remains constant after several brake applications, measure wheel turning torque necessary to rotate wheels with brakes applied.
To measure, shift transmission into Neutral, and raise front wheels. Apply brakes with a minimum force of 100 lbs. (45 kg), and hold about 15 seconds. With brakes applied, attempt to rotate front wheels with 75 ft. lbs. (102 N.m) of torque. If either wheel rotates, check front chamber of master cylinder, and replace parts as necessary. Repeat test for rear wheels.