Disc & Drum: Other Subaru Forester SF рестайлинг

BLEEDING PROCEDURES

Note. Start with brakes (wheels) connecting to the secondary chamber of the master cylinder.

Note. The time interval between 2 brake pedal operations (from the time the pedal is released to the time when it is depressed another time) shall be approximately 3 seconds.

Note. The air bleeder on each brake shall be released for one to 2 seconds.

Note. During bleeding operation, keep the brake reserve tank filled with brake fluid to eliminate entry of air. Brake pedal operating must be very slow. For convenience and safety, it is advisable to have 2 men working.

Note. If the master cylinder is disassembled or reservoir tank is empty, bleed the master cylinder.

Master Cylinder

1. Loosen wheel nuts, jack-up vehicle, support it with safety stands, and remove wheel.
2. Disconnect the brake line at primary and secondary sides.
3. Cover the master cylinder with vinyl bag.
4. Carefully depress and hold the brake pedal.
5. Close the outlet plug with your finger and release the brake pedal.
6. Repeat steps 4 and 5 until brake fluid is completely bled from outlet plug.
7. Remove the vinyl bag, then connect the brake pipe to master cylinder. Tighten to specification. See «TORQUE SPECIFICATIONS»(ref-162994-S28577697282004061600000) .
8. Using water, wash off the spilled brake fluid at the master cylinder surrounding, then wipe up the water.
9. Bleed air from the brake line. See «BRAKE LINE»(ref-162994-S21089882482004061600000) .

Brake Line

1. Make sure that there is no leak from joints and connections of the brake system.
2. Fit one end of vinyl tube into the air bleeder and put the other end into a brake fluid container.
3. Slowly depress the brake pedal and keep it depressed. Then, open the air bleeder to discharge air together with the fluid. Release air bleeder for one to 2 seconds. Next, with the bleeder closed, slowly release the brake pedal. Repeat these steps until there are no more air bubbles in the vinyl tube. Allow 3 to 4 seconds between 2 brake pedal operations.
4. Tighten air bleeder securely when no air bubbles are visible. Tighten air bleeder to specification. See «TORQUE SPECIFICATIONS»(ref-162994-S28577697282004061600000) .
5. Perform steps 1 - 4 for each brake in sequence. See «BLEEDING SEQUENCE»(ref-162994-S13912748372004061600000) . With all procedures completed, fully depress the brake pedal and keep it in that position for approximately 20 seconds to make sure that there is no leak evident in the entire system.
6. Perform sequence control (for models with ABS system). See SEQUENCE CONTROL under DIAGNOSIS & TESTING in appropriate ANTI-LOCK BRAKE SYSTEM article in BRAKES.
7. Check the pedal stroke. While the engine is idling, depress the brake pedal with a 110 lbs. (490 N) load and measure the distance between the brake pedal and steering wheel. With the brake pedal released, measure the distance between the pedal and steering wheel again. The difference between the 2 measurements must be more than specified. The specified pedal stroke for models without ABS is 3.54" (90 mm), and the pedal stroke for models equipped with ABS is 3.74" (95 mm). NOTE: Models Without ABS - If the distance is more than specifications, there is a possibility that air is in the brake line. Bleed air from the brake line. Models With ABS - If the distance is more than specifications, there is a possibility air is inside of the hydraulic unit. Therefore, air must be bled from the inside of the hydraulic unit to the brake pipes in accordance with the bleeding sequence control.
8. Recheck the brake stroke.
9. If distance is more than specified, there is a possibility that air is inside of the hydraulic unit. Repeat steps until pedal stroke meets 3.54" (90 mm) for models without ABS or 3.74" (95 mm) for models with ABS.
10. Add brake fluid to the required maximum level of reserve tank.
11. Test run the vehicle at low speed and apply brakes relatively hard 2 to 3 times to ensure that brakes provide normal braking action on all 4 wheels without dragging and uneven braking.

BLEEDING SEQUENCE

BRAKELINE BLEEDING SEQUENCE

BRAKE BOOSTER

Note. Testing without gauges cannot determine the exact portion which has failed, but it can provide a rough understanding of the nature of the failure if checking is conducted in accordance with the following procedures.

Note. When testing with gauges, connect gauges as shown. (Scheme 62) After bleeding air from pressure gauges, proceed to each check.

Scheme 62

Air Tightness (Without Gauges)

Note. In the event of defective operation, inspect the condition of the check valve and vacuum hose. Replace them if faulty and conduct the test again. If no improvement is observed, check precisely with gauges.

Start the engine, and run it for one to 2 minutes, then turn it off. Depress the brake pedal several times applying the same pedal force as that used in ordinary braking operations. The pedal stroke should be greatest on the first depression, and it should become smaller with each successive depression. If no change occurs in the pedal height while in a depressed state, the brake booster is faulty.

Air Tightness (With Gauges)

1. Start the engine and keep it running until a vacuum of 19.69 in. Hg (66.7 kPa) is indicated on vacuum gauge. DO NOT depress the brake pedal.
2. Stop the engine and watch the gauge. If the vacuum drop range is less than 0.98 in. Hg (3.3 kPa) within 15 seconds after stopping the engine, the brake booster is functioning properly. If defective, the cause may be one of the following: Check valve malfunction. Leak from vacuum hose. Leak from the shell jointed portion or stud bolt welded portion. Damaged diaphragm. Leak from valve body seal and bearing portion. Leak from plate and seal assembly portion. Leak from poppet valve assembly portion.

Loaded Air Tightness (Without Gauges)

Note. If faulty, check precisely with gauges.

Depress the brake pedal while engine is running, and turn off the engine while the pedal is still depressed. Keep the pedal depressed for 30 seconds; if no change occurs in the pedal height, the brake booster is functioning normally; if the pedal height increases, it is faulty.

Loaded Air Tightness (With Gauges)

1. Start engine and depress the brake pedal with pedal force of 44 lbs. (196 N). Keep engine running until a vacuum of 19.69 in. Hg. (66.7 kPa) is indicated on vacuum gauge while the pedal is still depressed.
2. Stop engine and watch vacuum gauge. If vacuum drop range is less than 0.98 in. Hg. (3.3 kPa) within 15 seconds after stopping engine, brake booster is functioning properly. If defective, see «AIR TIGHTNESS (WITH GAUGES)»(ref-162994-S41874243972004061600000) .

Lack Of Boosting Action (With Gauges)

Turn off engine, and set vacuum gauge reading to "0". Then, check fluid pressure when brake pedal is depressed. Pressure must be greater than the standard value. See FLUID PRESSURE SPECIFICATION table.

LACK OF BOOSTING ACTION FLUID PRESSURE SPECIFICATIONS

Boosting Action (With Gauges)

Set vacuum gauge reading at 19.69 in. Hg. (66.7 kPa) by running engine. Then, check fluid pressure when brake pedal is depressed. Pressure must be greater than the standard value. See BOOSTING ACTION FLUID PRESSURE SPECIFICATION table.

BOOSTING ACTION FLUID PRESSURE SPECIFICATIONS