Master Cylinder Bleeding

When a new brake master cylinder has been installed, or the brake system emptied or partially emptied, fluid may not flow from the brake master cylinder reservoir during normal bleeding. It may be necessary to prime the system using the following procedure:

1. Use a line wrench to remove the brake lines from the brake master cylinder.
2. Install short brake lines in the brake master cylinder and position them so that they point back into the brake master cylinder reservoir, and the ends of the brake lines are submerged in brake fluid.
3. Fill the brake master cylinder reservoir with new High Performance DOT 3 Motor Vehicle Brake Fluid C6AZ-19542-AB or DOT 3 equivalent fluid meeting Ford specification ESA-M6C25-A, DOT 3.
4. Cover the brake master cylinder reservoir with a shop towel.

CAUTION: Brake fluid is harmful to painted and plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.

5. Pump the brakes until clear, bubble-free fluid comes out of both temporary brake lines.
6. Remove the short brake lines and reinstall the brake lines.
7. Bleed the brake master cylinder using the following procedure:
a. Have an assistant pump the brake pedal ten times and then hold firm pressure on the brake pedal.
b. Loosen the rear-most brake line flare nuts with a line wrench until a stream of brake fluid comes out. Have an assistant maintain pressure on the brake pedal until the brake line fitting is tightened again.
c. Repeat this operation until clear, bubble-free fluid comes out from around the brake line fitting.
d. Repeat this bleeding operation at the front brake line flare nut.

8. If any of the brake lines have been removed, it may be helpful to prime the system by gravity bleeding it. This should be done after the brake master cylinder is primed and bled.

To gravity bleed the brake system:
a. Fill the brake master cylinder reservoir with new High Performance DOT 3 Motor Vehicle Brake Fluid C6AZ-19542-AB or DOT 3 equivalent fluid meeting Ford specification ESA-M6C25-A, DOT 3.
b. One at a time, loosen both the rear bleeder screws and leave them open until clear brake fluid flows out. Be sure to check the brake master cylinder reservoir fluid level often and not let it run dry.
c. Tighten the rear bleeder screws to 6-8 Nm (53-77 inch lbs.).
d. One at a time, loosen the front bleeder screws. Leave the front bleeder screws open until clear fluid flows out. Be sure to check the brake master cylinder reservoir level often and not let it run dry. Tighten the front bleeder screws to 6-8 Nm (53-77 inch lbs.).

9. After the brake master cylinder has been primed the brake lines bled at the brake master cylinder, and the brake system gravity bled, normal brake system bleeding can resume at each wheel.

NOTE: Since front-wheel drive cars do not normally use hold-off valves, this method works on all four wheels.