Service Brake

Check the free play of brake pedal by pulling up the pedal with a force of 10 N (1 kgf, 2 lb) or less.
Brake pedal free play (Pulling up direction of pedal)

0.5 - 2.0 mm (0.02 - 0.08 in)

Fig 1: Checking Free Play Of Brake Pedal
Courtesy of SUBARU OF AMERICA, INC.
If the free play is out of specifications above, adjust the brake pedal as follows.
1. Make sure the engine is off. (No vacuum is applied to brake booster.)
2. There should be play between brake booster clevis and pin at brake pedal installing portion. [Pulling up the brake pedal pad with a force of 10 N (1 kgf, 2 lb) or less to a stroke of 0.5 to 2.0 mm (0.02 to 0.08 in).]
3. If there is no free play between clevis pin and clevis, turn brake switch adjusting nut until the clearance between stopper and screw of brake switch becomes 0.3 mm (0.012 in).
  
  Fig 2: Identifying Pedal Free Play
  Courtesy of SUBARU OF AMERICA, INC.
Check the pedal stroke.
While the engine is idling, depress the brake pedal with a 490 N (50 kgf, 110 lb) load and measure the distance between the brake pedal and steering wheel. With the brake pedal released, measure the distance between pedal and steering wheel again. The pedal stroke is normal if the difference between two measured values is the specified value or less. If the measured value is the specification or more, there is possibility of entering air in hydraulic unit.

Brake pedal stroke A:

95 mm (3.7 in)/ 490 N (50 kgf, 110 lb) or less

Fig 3: Identifying Brake Pedal Stroke
Courtesy of SUBARU OF AMERICA, INC.
Check to see if air is in the hydraulic brake line by the feel of pedal operation. If air appears to exist in the line, bleed it from the system.
Check for even operation of all brakes, using a brake tester or by driving the vehicle for a short distance on a straight road.