Q: How do you remove and overhaul a master cylinder on Ford Bronco?
A: To remove the Brake Master Cylinder, start by disconnecting the cable from the negative battery terminal. If the vehicle has a power brake booster system, push the brake pedal down to expel the vacuum. For manual brakes, disconnect the wires from the brake light switch and remove the nut and shoulder bolt securing the Brake Master Cylinder pushrod to the brake pedal. On later models, disconnect the fluid level indicator connector at the reservoir. Place newspapers or rags under the Brake Master Cylinder to catch any leaking brake fluid. Use a suction device to remove as much brake fluid from the reservoir as possible. Unscrew the Brake Lines from the primary and secondary outlets of the Brake Master Cylinder and plug the ends of the lines. Remove the fasteners securing the Brake Master Cylinder to the firewall or power booster. Pull the Brake Master Cylinder forward and lift it out of the vehicle, being careful not to let any fluid contact the paint. To overhaul the Brake Master Cylinder, clean the exterior with brake system cleaner and remove the reservoir cover or cap. Pour any remaining brake fluid into a container. Remove the secondary piston stop bolt and the snap-ring from the primary piston assembly. Remove the secondary piston assembly by tapping the cylinder against a wood block. Examine the bore of the cylinder for any damage. If necessary, replace the Brake Master Cylinder body. Clean all parts with brake system cleaner and dip the new or overhauled secondary and primary piston assemblies into clean brake fluid before installing them into the cylinder bore. Depress the primary piston and install the snap-ring. Push in the primary piston and tighten the secondary piston stop screw. To install the Brake Master Cylinder, it is necessary to bleed the system. Bench bleed the Brake Master Cylinder by supporting it in a vise, filling the reservoir with brake fluid, and stroking the primary piston while sealing the outlet ports with fingers. Install the outlet port plugs quickly after the final stroke. If the vehicle has a power brake booster system, check the pushrod-to-mounting-face distance and adjust if necessary. Install the Brake Master Cylinder following the reverse of the removal procedure and then bleed the hydraulic system.