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For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Park Avenue 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Hydraulic Brake System Bleeding

Hydraulic Brake System Bleeding Bleeding Brake System

Caution: Do not move the vehicle until a firm brake pedal is obtained. Air in the brake system can cause the loss of brakes with possible personal injury.

Whenever air gets into the brake hydraulic system you must bleed the system to remove the air. The hydraulic systems at all four wheel positions may have to be bled if air had entered the system due to a low fluid level or from the brake pipes having been disconnected at the master cylinder. If a brake pipe is disconnected at one wheel, only that caliper needs to be bled. If the pipes are disconnected at any fitting located between the master cylinder and the wheels, the brake system served by the disconnected pipe must be bled.

Hydraulic Brake System Bleeding Manual Bleeding

Tools Required

    • J 21472 Bleeder Wrench
    • J 28434 Bleeder Wrench

    Object Number: 40374 Size: SH
  1. Deplete the booster reserve by applying the brakes several times with the engine off until all of the reserve is depleted.

    2. Do not allow paint to touch painted surfaces.

  2. Fill the master cylinder reservoir to the full level mark using only Delco Supreme II Brake fluid or the equivalent, DOT-3 brake fluid, as specified. Refer to Maintenance and Lubrication in General Information.
    3. • Maintain the fluid level in the reservoir during the bleeding.
    • Have an assistant press the brake pedal when needed during the bleeding.

    Important: Be sure the master cylinder reservoir cap is installed before the brake pedal is pressed . This prevents the brake fluid from spraying from the reservoir.

  3. If the master cylinder is known or suspected to have air in the bore, bleed it as follows before bleeding the calipers.
    4. 3.1. Loosen the forward brake pipe connection at the master cylinder.
    3.2. Allow the brake fluid to flow from the connector port.

    Maintain the reservoir fluid level.

    3.3. Tighten the forward brake pipe on the master cylinder.
    3.4. Depress the brake pedal slowly one time and hold.
    3.5. Loosen the forward brake pipe connection again to purge air from the bore.
    3.6. Tighten the connection and then slowly release the brake pedal.

    Tighten
    Tighten the brake pipe connection to 15 N·m (11 lb ft).

    3.7. Wait 15 seconds.
    3.8. Repeat the sequence, including the 15 second wait. Repeat until all of the air is removed from the bore.
    3.9. Repeat this procedure and bleed the master cylinder at the rear connection.
  4. Bleed the individual wheel calipers only after all of the air is removed from the master cylinder.

    5. If the calipers dot not contain air bleeding is not needed.

  5. If all of the wheel circuits must be bled use the following sequence:
    6. 5.1. Right Rear
    5.2. Left Rear
    5.3. Right Front
    5.4. Left Front
  6. Raise the vehicle and suitably support.

    7. Refer to Raising and Supporting the Vehicle in General Information.

  7. Remove the bleeder valve cap and place the proper size box-end wrench or J 21472 /J 28434 , over the bleeder valve.
  8. Attach a transparent tube to the bleeder valve.
  9. Submerge the other end of the tube in a clear container partially filled with clean brake fluid.
  10. Depress the brake pedal slowly one time and hold.

    11. Use slow pedal action. Rapid pedal pumping pushes the master cylinder secondary piston down the bore in a way that makes bleeding the system difficult.

    10.1. Loosen the bleeder valve to purge the air from the caliper.

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    10.2. Tighten the bleeder valve.

    Tighten
    Tighten the caliper bleeder valve to 13 N·m (115 lb ft).

    10.3. Slowly release the brake pedal.
    10.4. Wait fifteen seconds.
    10.5. Repeat the sequence, including the 15 second wait, until all of the air is removed.

    The sequence may need to be bled ten times or more to remove all of the air.

  11. Install the bleeder valve caps.
  12. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  13. Fill the master cylinder to the full mark.
  14. Check the brake pedal for sponginess.
  15. Repeat the entire bleeding procedure to correct the sponginess if found.
  16. Pressure bleed the brake system using scan tool, after the manual bleeding procedure is complete.

Hydraulic Brake System Bleeding Pressure Bleeding

Tools Required

    • J 21472 Bleeder Wrench
    • J 28434 Bleeder Wrench
    • J 29532 Bleeder Ball
    • J 35589 Bleeder Adapter

    Notice: Pressure bleeding equipment must be of the diaphragm type. It must have a rubber diaphragm between the air supply and the brake fluid to prevent air, moisture, oil and other contaminants from entering the hydraulic system.

    Important: The correct master cylinder bleeder adapter must be used to avoid the possible damage to the master cylinder reservoir.


    Object Number: 40374 Size: SH
  1. Fill the master cylinder reservoir to the full mark using only Delco Supreme II Brake Fluid or the equivalent, DOT-3 brake fluid, as specified in Maintenance and Lubrication in General Information.
  2. Install the J 35589 to the master cylinder.
  3. Charge the J 29532 to 140 to 172 kPa (20 to 25 psi).
  4. Connect the J 29532 hose to the adapter and open the line valve.
  5. Raise and suitably support the vehicle. Refer to Vehicle Lifting and Jacking in General Information.
  6. If all of the wheel circuits must be bled use the following sequence:
    7. 6.1. Right Rear
    6.2. Left Rear
    6.3. Right Front
    6.4. Left Front
  7. Remove the bleeder valve cap and place the proper size box-end wrench or J 21472 /J 28434 , over the bleeder valve.
  8. Attach a transparent tube to the bleeder valve.
  9. Submerge the other end of the tube in a clear container partially filled with clean brake fluid.
  10. Loosen the bleeder valve a 3/4 turn.
  11. Allow the fluid to flow until no air is found in the fluid.

    12. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  12. Tighten the bleeder valve.

    13. Tighten
    Tighten the caliper bleeder valve to 13 N·m (115 lb ft).

  13. Repeat steps 6 through 10 until all of the calipers have been bled.
  14. Install the bleeder caps.
  15. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  16. Check the brake pedal for sponginess.
  17. Repeat the entire bleeding procedure to correct the sponginess if found.
  18. Remove the J 29532 and the J 35589 .
  19. Fill the master cylinder to the full mark. Refer to Master Cylinder Reservoir Filling .
  20. Pressure bleed the brake system using scan tool, after the manual bleeding procedure is complete.