LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2022 >> Ascent Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 20 (Brake System) >> Air Bleeding >> Procedure >> Brake Line
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Brake Line

WARNING: This page is about a different car, the 2021 Subaru Ascent. However, it is still accessible from the selected car via links, so may be relevant.
  1. When the master cylinder assembly is replaced or the oil reservoir COMPL is empty, bleed the master cylinder assembly before bleeding the brake line. Ref. to BRAKE>Air Bleeding>PROCEDURE> MASTER CYLINDER .
  2. Fill the oil reservoir COMPL of the master cylinder assembly with brake fluid.
    NOTE: While bleeding air, keep the oil reservoir COMPL filled with brake fluid to prevent entry of air.
  3. Attach one end of a transparent vinyl tube to the bleeder screw, and the other end to a brake fluid collection container.
    G13199781Courtesy of SUBARU OF AMERICA, INC.
  4. Loosen the bleeder screw, and then repeat the full stroke depressing operation of the brake pedal, until brake fluid in the transparent vinyl tube has no more air bubbles.
    NOTE: Air bubbles are removed after repeating the depressing operation 15 times or more for the front caliper, and 20 times or more for the rear caliper.
  5. Perform the steps 2) to 4) above on each brake caliper.
    NOTE: Perform in the order starting from the front RH → front LH → rear LH → rear RH.
  6. Tighten the loosened bleeder screw, repeat firmly depressing of the brake pedal 5 to 6 times, and then depress and hold the brake pedal.
  7. Loosen the bleeder screw to drain the brake fluid. When the brake pedal reaches the full stroke position, immediately tighten the bleeder screw and return the brake pedal.
  8. Repeat steps  6) and 7) until there are no more air bubbles in the transparent vinyl tube.
  9. Perform the steps  6) to 8) above on each brake caliper.
    NOTE: Perform in the order starting from the front RH → front LH → rear LH → rear RH.
  10. Perform the sequence control mode for the hydraulic control unit in both ABS and VDC systems.
    CAUTION:
    • If there is a possibility that air enters the pressure control section in the hydraulic control unit, perform steps 11) to 16).
    • For normal air bleeding operation, do not operate the sequence control for the hydraulic control unit. (Operating the sequence control may let air in the normal air bleeding passages move to the pressure control section.)
    NOTE:
    • Normal air bleeding operation does not help bleed air that enters the pressure control section in the hydraulic control unit.
    • If there is a possibility that air enters the pressure control section in the hydraulic control unit (if VDC or ABS operates with air contained in the normal air bleeding passage), perform the sequence control mode for both of the ABS and VDC systems.
  11. Perform the ABS sequence control mode. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>ABS SEQUENCE CONTROL .
    CAUTION: Be sure to perform the ABS sequence control mode first.
  12. Perform the air bleeding operation of steps 3) and 4) for the bleeder screw on each caliper.
    NOTE:
    • Perform in the order starting from the front RH → front LH → rear LH → rear RH.
    • As a reference, the number of the full stroke depressing operation is six times.
  13. Perform the VDC sequence control mode. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC SEQUENCE CONTROL .
  14. Perform the air bleeding operation of steps 3) and 4) for the bleeder screw on each caliper.
  15. Repeat from steps  11) to 14) for three cycles.
  16. In case air still remains at step 15), repeat steps 11) to 14) again until all air is removed.
  17. Fill the oil reservoir COMPL with brake fluid up to the "MAX" level.
  18. Tighten the bleeder screw to the specified torque.

    Tightening torque:  

    17 N.m (1.7 kgf-m, 12.5 ft-lb)

  19. Install the bleeder cap to each bleeder screw.
  20. Check that there are no brake fluid leaks at the flare nut portion or in the entire brake system.
  21. After inspection, wipe off fluid around each bleeder screw and the oil reservoir COMPL.
  22. Perform a road test and ensure that the brakes operate normally.
scientia non olet · About LEMON Manuals