Ranger 4WD V6-245 4.0L VIN X SFI (1999)
9. Remove the short brake tubes and install the master cylinder outlet tubes.
10. Loosen a brake outlet tube at the 4WABS Hydraulic Control Unit (HCU).
11. NOTE: Refill the brake master cylinder reservoir as necessary.
Have an assistant depress and hold the brake pedal.
12. Tighten the outlet tube fitting at the HCU.
13. Repeat the above three steps until no air bubbles are seen in the expelled brake fluid.
14. Repeat the above four steps for the remaining master cylinder outlet tube.