LEMON Manuals: Even more car manuals for everyone
Home >> Subaru >> 2025 >> Forester Wilderness >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Brake System) >> Air Bleeding >> Procedure >> Brake Line

Brake Line

WARNING: This page is about a different car, the 2023 Subaru Ascent. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
  • During the operation, disconnect the ground terminal from the battery sensor to prevent the electric brake booster from starting.
  • Do not let brake fluid come into contact with the painted surface of the vehicle body. Wash away with water immediately and wipe off if it is spilled by accident.
  • Do not mix different kinds of brake fluid. Mixing different brands of fluid, or mixing different grades of fluid (even if they have the same brand name), may lead to severe accidents due to reduced brake fluid performance.
  • When refilling brake fluid, do not allow dirt or dust to get into the reservoir tank.
  • Always use new SUBARU genuine brake fluid when replacing or refilling the fluid. Do not reuse drained brake fluid.
  • For convenience and safety, perform the work with 2 people.
  • During the operation, keep the reservoir tank filled with brake fluid at MIN level or higher to prevent entry of air.
  • After air bleeding operation, wipe off fluid around each bleeder screw and the reservoir tank.
  1. Disconnect the ground terminal from battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
  2. When the master cylinder assembly is replaced or the reservoir tank is empty, bleed air from the master cylinder assembly before bleeding air from the brake line. Ref. to BRAKE>AIR BLEEDING>PROCEDURE>MASTER CYLINDER .
  3. Fill the reservoir tank of the master cylinder assembly with brake fluid.
    NOTE: While bleeding air, keep the reservoir tank filled with brake fluid to prevent entry of air.
  4. 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.
  5. 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.
  6. Perform the steps  3 to  5 above on each brake caliper.
    NOTE: Perform in the order starting from the front RH → front LH → rear LH → rear RH.
  7. Tighten the loosened bleeder screw, repeat firmly depressing of the brake pedal quickly 5 to 6 times, and then depress and hold the brake pedal.
  8. 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.
  9. Repeat steps  7 and  8 until there are no more air bubbles in the transparent vinyl tube.
  10. Perform the steps  7 to  9 above on each brake caliper.
    NOTE: Perform in the order starting from the front RH → front LH → rear LH → rear RH.
  11. Connect the ground terminal to battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
  12. 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  13 to  18.
    • 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.
  13. 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.
  14. Perform the air bleeding operation of steps  4 and  5 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.
  15. Perform the VDC sequence control mode. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC SEQUENCE CONTROL .
  16. Perform the air bleeding operation of steps  4 and  5 for the bleeder screw on each caliper.
  17. Repeat from steps  13 to  16 for three cycles.
  18. In case air still remains at step  17), repeat steps  13 to  16 again until all air is removed.
  19. Fill the reservoir tank with brake fluid up to the "MAX" level.
  20. Tighten the bleeder screw to the specified torque.

    Tightening torque: 

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

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