Subaru Outback manuals

Subaru Outback: Brake Booster

A: REMOVAL

CAUTION: Do not allow brake fluid to come in contact with the painted surface of the vehicle body. If it does, wash off with water and wipe away completely.

1) Disconnect the ground cable from battery.

2) Drain brake fluid from the reservoir tank completely.

3) Remove the master cylinder assembly.

CAUTION: In order to prevent the contact of the bracket and check valve, be sure to loosen the master cylinder mounting nut while holding the bracket with hand. Otherwise it may deform the bracket.

Subaru Outback. Brake

  1. Disconnect the fluid level gauge connector (a).
  2. Disconnect the brake pipe (b).
  3. Remove the nut (c), and slowly remove the master cylinder from the brake booster.

Subaru Outback. Brake

4) Remove the brake booster.

CAUTION:

Subaru Outback. Brake

  1. Remove the clamp and remove the vacuum hose.

Subaru Outback. Brake

  1. Non-turbo model
  2. Turbo model
  1. Remove the clips, and remove the instrument panel side cover LH.

Subaru Outback. Brake

  1. Remove the clips and data link connector, and remove the instrument panel lower cover under.

Subaru Outback. Brake

  1. Remove the screws and clips and release the claws, and remove the instrument panel lower cover while disconnecting the harness connectors.

Subaru Outback. Brake

  1. Remove the bolts, and remove the knee guard panel.

Subaru Outback. Brake

  1. Remove the snap pin (a) and clevis pin (b), and remove the operating rod from the brake pedal.

NOTE:

Subaru Outback. Brake

  1. Remove the nut and remove the brake booster.

NOTE:

Subaru Outback. Brake

B: INSTALLATION

1) Check and adjust the operating rod of the brake booster.

  1. Measure the length between the brake booster mounting surface and clevis pin hole.
  2. If it is not within specification, loosen the lock nut, rotate the brake booster operating rod to adjust the rod length.

Specification L: 136.5 mm (5.37 in)

Subaru Outback. Brake

2) Install each part in the reverse order of removal.

CAUTION:

Subaru Outback. Brake

  1. Primary piston
  2. Seal sub ASSY
  3. Install the seal sub assembly to this surface.

Subaru Outback. Brake

Tightening torque:
Brake booster: 18 N*m (1.84 kgf-m, 13.3 ft-lb)
Master cylinder: 13 N*m (1.33 kgf-m, 9.6 ft-lb)
Brake pipe flare nut: 19 N*m (1.94 kgf-m, 14.0 ft-lb)
Operating lock nut: 22 N*m (2.24 kgf-m, 16.2 ft-lb)

3) Bleed air from the brake system. <Ref. to BR-54, PROCEDURE, Air Bleeding.>

4) Perform a road test to make sure the brakes do not drag.

C: INSPECTION

1. OPERATION CHECK (WITHOUT GAUGES)

CAUTION: When checking operation, be sure to apply the parking brake securely.

This method can not determine exactly what part is defective. But it is possible to identify the outline of the defect by performing the check according to the following procedures.

Start the engine, and idle it for 1 to 2 minutes, then turn it OFF. Depress the brake pedal several times applying the normal pedal force. The pedal stroke should be the longest at the 1st depression, and it should become shorter at each successive depression. If no change occurs in the pedal height when pressed, the brake booster is faulty.

Subaru Outback. Brake

  1. Normal
  2. Not OK
  3. 1st
  4. 2nd
  5. 3rd

NOTE:

 

1) While the engine is OFF, depress the brake pedal several times applying the same pedal force, to check for a change in pedal height.

Subaru Outback. Brake

  1. When engine is stopped
  2. When engine is started

2) With the brake pedal depressed, start the engine.

3) As the engine starts, the brake pedal should move slowly toward the floor. If the pedal height does not change, the brake booster is faulty.

NOTE: If faulty, check precisely with gauges.

Depress the brake pedal while the engine is running, and turn the engine to OFF while the pedal is depressed.

Keep the pedal depressed for 30 seconds. If the pedal height does not change, the function of brake booster is normal. If the pedal height increases, it is faulty.

NOTE: If faulty, check precisely with gauges.

2. OPERATION CHECK (WITH GAUGES)

CAUTION: When checking operation, be sure to apply the parking brake securely.

Connect the gauge as shown in the figure. After bleeding air from the pressure gauge, perform each check.

Subaru Outback. Brake

  1. Pressure gauge
  2. Vacuum gauge
  3. Adapter hose
  4. Vacuum hose
  5. Pedal force gauge

Air tightness check

1) Start the engine and keep it running until vacuum pressure indicates point A of the vacuum gauge = 66.7 kPa (500 mmHg, 19.69 inHg). Do not depress the brake pedal at this time.

Subaru Outback. Brake

  1. Pressure gauge
  2. Vacuum gauge

2) Stop the engine and check the gauge. If the vacuum pressure drop within 15 seconds after stopping the engine is 3.3 kPa (25 mmHg, 0.98 inHg) or less, the function of brake booster is normal.

If faulty, the cause may be one of the following.

 

1) Start the engine and depress the brake pedal with a pedal force of 196 N (20 kgf, 44 lbf). Keep the engine running and keep the pedal pressed until a vacuum of point B = 66.7 kPa (500 mmHg, 19.69 inHg) is indicated on the vacuum gauge.

Subaru Outback. Brake

  1. Pressure gauge
  2. Vacuum gauge
  3. Pedal force gauge
  4. Depressed

2) Stop the engine and check the vacuum gauge.

If the vacuum pressure drop within 15 seconds after stopping the engine is 3.3 kPa (25 mmHg, 0.98 inHg) or less, the function of brake booster is normal.

If defective, refer to "AIR TIGHTNESS CHECK".

<Ref. to BR-49, INSPECTION, Brake Booster.>

3) If the brake booster is faulty, replace it with a new part.

Turn the engine OFF, and set the value of the vacuum gauge to "0". Then, check the fluid pressure when the brake pedal is depressed. The pressure must be greater than the specification listed.

Subaru Outback. Brake

Set the vacuum gauge reading to 66.7 kPa (500 mmHg, 19.69 inHg) with the engine running. Then, check the fluid pressure when the brake pedal is depressed. The pressure must be greater than the specification listed.

Subaru Outback. Brake

Brake Fluid

A: INSPECTION

1) Check that the amount of brake fluid is between the lines of "MIN" and "MAX". If out of the specified range, refill or drain the fluid. If the fluid level is close to "MIN", check the brake pad for wear and refill the fluid.

2) Check the fluid for discoloration. If the fluid is extremely discolored, replace with the new fluid.

B: REPLACEMENT

CAUTION:

NOTE:

1) Lift up the vehicle and set rigid racks at the specified locations, or keep the vehicle lifted.

2) Remove both the front and rear wheels.

3) Drain brake fluid from the reservoir tank.

4) Refill the reservoir tank with recommended brake fluid.

Recommended brake fluid: FMVSS No. 116, DOT3, or DOT4

Perform the same procedure as for bleeding the brake line, until new brake fluid comes out from vinyl tube.

<Ref. to BR-54, PROCEDURE, Air Bleeding.>

Air Bleeding

A: PROCEDURE

CAUTION:

1. MASTER CYLINDER

NOTE:

1) Fill the reservoir tank of the master cylinder with brake fluid.

NOTE: While bleeding air, keep the reservoir tank filled with brake fluid to prevent entry of air.

2) Disconnect the brake line at primary and secondary sides.

3) Wrap the master cylinder with a plastic bag.

4) Depress the brake pedal slowly and hold it.

Subaru Outback. Brake

5) Plug the outlet plug with your finger, and then release the brake pedal.

Subaru Outback. Brake

6) Repeat the step 4) and 5) several times.

7) Remove the plastic bag.

8) Install the brake pipe to the master cylinder.

Tightening torque: Brake pipe flare nut: 19 N*m (1.94 kgf-m, 14.0 ft-lb)

9) Bleed air from the brake line. <Ref. to BR-54, BRAKE LINE, PROCEDURE, Air Bleeding.>

2. BRAKE LINE

1) When the master cylinder is replaced or the reservoir tank is empty, bleed the master cylinder before bleeding the brake line. <Ref. to BR-54, MASTER CYLINDER, PROCEDURE, Air Bleeding.>

2) Fill the reservoir tank of the master cylinder with brake fluid.

NOTE: While bleeding air, keep the reservoir tank filled with brake fluid to prevent entry of air.

3) Attach one end of the vinyl tube to the air bleeder and the other end to the brake fluid container.

Subaru Outback. Brake

4) Depress the brake pedal several times, and hold it.

5) Loosen the air bleeder screw to drain brake fluid. Tighten the air bleeder quickly, and release the brake pedal.

6) Repeat the steps 4) to 5) until there are no more air bubbles in the vinyl tube.

7) Repeat the steps from 2) to 6) above to bleed air from each wheel.

NOTE: Perform air bleed starting in the order from the farthest wheel cylinder from the master cylinder.

8) Securely tighten the air bleeder screws.

Tightening torque: Air bleeder screw: 8 N*m (0.82 kgf-m, 5.9 ft-lb)

9) Check that there are no brake fluid leaks in the entire brake system.

10) Check the pedal stroke.

Run the engine at idle after warming up the engine, and depress the brake pedal with a force of 500 N (51 kgf, 112 lbf). Measure the distance between the brake pedal and steering wheel. Release the pedal, and measure the distance between pedal and steering wheel again.

Subaru Outback. Brake

  1. Steering wheel
  2. Toe board

Specification of pedal stroke:
When depressing the pedal with a force of 500 N (51 kgf, 112 lbf).
110 mm (4.33 in) or less

11) If the distance is more than specification, there is a possibility of air being caught in the brake line. Bleed the brake line of all air until the pedal stroke meets the specification.

12) Operate the hydraulic control unit in the sequence control mode. <Ref. to VDC-17, ABS Sequence Control.>

13) Check the pedal stroke again.

14) If the distance is more than specification, there is a possibility of air being caught in the hydraulic unit. Repeat above steps 2) to 9) until the pedal stroke meets the specification.

15) Fill the reservoir tank with brake fluid up to the "MAX" level.

16) Perform a road test and ensure that the brakes operate normally.

READ NEXT:

 Brake Hose

A: REMOVAL 1. FRONT BRAKE HOSE 1) Separate the brake pipe (b) from brake hose (a) using a flare nut wrench. 2) Remove the clamp, strut mounting bolt and union bolt, and remove the front brake hose.

 Stop Light Switch

A: REMOVAL 1) Disconnect the ground cable from battery. 2) Remove the instrument panel lower cover. Remove the clips, and remove the instrument panel side cover LH. Remove the clips and data li

 Parking Brake

General Description A: SPECIFICATION B: COMPONENT 1. PARKING BRAKE (REAR DISC BRAKE) Back plate Retainer Lever Parking brake shoe (Primary) Parking brake shoe (Secondary) Strut spring Strut

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 Front fog light (if equipped)

NOTE It may be difficult to replace the bulbs. We recommend that you have the bulbs replaced by your SUBARU dealer if necessary. 1. Pull off the fender lining. Refer to “Pulling off the fender lining” F11-7. 2. Disconnect the electrical connector. 1) For left-hand side 2) For right-ha

 Wheel replacement

When replacing wheels due, for example, to damage, make sure the replacement wheels match the specifications of the wheels that are fitted as standard equipment. Replacement wheels are available from SUBARU dealers. WARNING Use only those wheels that are specified for your vehicle. Wheels not

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