Master Cylinder

NOTE:

When the master cylinder assembly is replaced or the reservoir tank is empty, bleed the brake master cylinder and the clutch master cylinder (MT model).
For air bleed procedure of the clutch fluid, refer to "CLUTCH SYSTEM" information. Ref. to CLUTCH SYSTEM>Clutch Fluid Air Bleeding>PROCEDURE .
If bleeding of the master cylinder assembly is not necessary, omit the following procedures, and perform bleeding of the brake line. Ref. to BRAKE>Air Bleeding>PROCEDURE>BRAKE LINE .

Install the brake pipe to the master cylinder assembly.
1. Screw and tighten the flare nut (b) so that the end of the nut contacts the back side of the brake pipe flare, while pressing the brake pipe (a) toward the master cylinder assembly side.
  CAUTION: Be careful not to make scratches or other damage to the inside surface of the brake pipe flare.
  
  Tightening torque:
  
  Brake pipe flare nut: 19 N.m (1.9 kgf-m, 14 ft-lb)
  
  Fig 1: Pressing Brake Pipe Toward Master Cylinder Assembly Side
  Courtesy of SUBARU OF AMERICA, INC.
Fill the reservoir tank of the master cylinder assembly with brake fluid.
NOTE:
- Replenish brake fluid to the MAX level.
- During the operation, keep the reservoir tank filled with brake fluid at MIN level or higher to prevent entry of air.
Attach a transparent vinyl tube to the bleeder - screw of the right front caliper body assembly that is the closest from the VDC control module & hydraulic control unit, and the other end of the vinyl tube to a collection container.
Loosen the bleeder - screw, depress the brake pedal slowly and hold it.
Tighten the bleeder - screw, and release the brake pedal quickly.
Repeat steps 4) and 5) until there are no more air bubbles in the brake fluid in the vinyl tube.
NOTE: Air bubbles are removed after repeating the procedures six to seven times.
Attach a transparent vinyl tube to the bleeder - screw of the left front caliper body assembly, and the other end of the vinyl tube to a brake fluid collection container.
Repeat steps 4) and 5) until there are no more air bubbles in the brake fluid in the vinyl tube.
NOTE:
- Air bubbles are removed after repeating the procedures seven to eight times.
- With the procedures so far, bleed is completed for the air that entered in the master cylinder, front brake piping hose passages and front caliper.
Next, perform the following procedures to bleed air that entered in the rear brake piping hose passages and rear caliper from the hydraulic unit.
Attach a transparent vinyl tube to the bleeder - screw of the left rear caliper body assembly, and the other end of the vinyl tube to a brake fluid collection container.
Loosen the bleeder - screw, and repeat the full stroke depressing operation of the brake pedal slowly, until the brake fluid in the transparent vinyl tube has no more air bubbles, then tighten the bleeder - screw.
NOTE: By repeating the procedures 15 times or more, air that entered in the rear brake pipe passages from the VDC control module & hydraulic control unit reaches the bleeder - screw of the left rear caliper body assembly and is discharged.
Attach a transparent vinyl tube to the bleeder - screw of the right rear caliper body assembly, and the other end of the vinyl tube to a brake fluid collection container.
Perform step 10).
NOTE:
- By repeating the procedures 10 times or more, air that entered in the rear brake pipe passages from the VDC control module & hydraulic control unit reaches the bleeder - screw of the right rear caliper body assembly and is discharged.
- With the procedures so far, bleed is completed for the air that entered in the rear brake piping hose passages and rear caliper from the hydraulic unit.
Lastly, perform the following procedures to bleed air that may remain in areas where the brake fluid flow stands.
Attach a transparent vinyl tube to the bleeder - screw of the right front caliper body assembly, and the other end of the vinyl tube to a brake fluid collection container.
After repeating firmly depressing of the brake pedal quickly five or six times, depress and hold the pedal.
Loosen the bleeder - screw to drain brake fluid. When the brake pedal reaches the full stroke position, tighten the bleeder - screw quickly, and release the brake pedal.
Repeat steps 14) and 15) until there are no more air bubbles in the transparent vinyl tube.
NOTE: Repeat the procedures approximately four to five times.
Repeat steps 14) to 16) above for each brake caliper.
NOTE: Bleed air in the order starting from the front RH → front LH → rear LH → rear RH.
Tighten the bleeder - screw to the specified torque.
Tightening torque:

Bleeder - screw: 8 N.m (0.82 kgf-m, 5.9 ft-lb)
Install the cap - bleeder to each bleeder - screw.