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Hydraulic Brake System Bleeding Manual Bleeding

The time required to bleed the hydraulic system can be reduced if the master cylinder reservoir is filled with brake fluid and as much air as possible is expelled before the master cylinder is installed on the vehicle. Pumping the piston can evacuate the air from the piston cavities.

Power brakes require the vacuum reserve be depleted by applying the brakes several times with the engine off. Care must be taken to prevent brake fluid from contacting any painted surface.


    Object Number: 171922 Size: SH
  1. Fill the master cylinder reservoir with brake fluid and keep the reservoir at least half full of fluid during the bleeding operation.
  2. If the master cylinder is known or suspected to have air in the bore, then it must be bled in the following manner, before bleeding any caliper:
    3. 2.1. Disconnect the forward (blind end) brake pipe connection at the master cylinder.
    2.2. Allow the brake fluid to fill the master cylinder piston bore until it begins to flow from the forward pipe connector port.
    2.3. Connect the forward brake pipe to the master cylinder and tighten.

    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.

    2.4. Depress the brake pedal slowly one time and hold. Loosen the forward brake pipe connection at the master cylinder to purge air from the bore. Tighten the connection and then release the brake pedal slowly. Wait 15 seconds. Repeat the sequence, including the 15 second wait, until all air is removed from the bore.

    Tighten
    Tighten the brake pipe tube nut to 16 N·m (12 lb ft).

    2.5. When clear fluid flows from the forward connection, repeat steps 1 and 2 to bleed the master cylinder at the rear (cowl) connection.

    Object Number: 63934 Size: SH
  3. Individual brake calipers are bled only after all air is removed from the master cylinder. If it is known that the brake calipers do not contain any air, then it will not be necessary to bleed them.
    4. 3.1. Place a proper size box end wrench, or equivalent, over the brake caliper bleed screw.
    3.2. Attach a clear tube over the screw.
    3.3. Submerge the other end of the tube in a clear container partially filled with brake fluid.
    3.4. Depress the brake pedal slowly one time and hold.
    3.5. Loosen the brake caliper bleed screw to purge the air from the cylinder.
    3.6. Tighten the brake caliper bleed screw and slowly release the pedal. Wait 15 seconds.

    Tighten
    Tighten the brake caliper bleed screw to 12 N·m (106 lb in).

    3.7. Repeat the sequence (including the 15 second wait), until all of the air is removed. It may be necessary to repeat the sequence ten or more times to remove all of the air.
    3.8. If it is necessary to bleed all of the brake calipers, the following sequence should be used:
             3.8.1. Right rear
             3.8.2. Left rear
             3.8.3. Right front
             3.8.4. Left front
    3.9. Test drive the vehicle. Check the brake pedal for sponginess.
    3.10. Ensure that vehicle exceeds 5 km/h (3 mph) for ABS modulator actuation (self-test). If after ABS modulation the brake pedal is spongy or soft, then re-bleed system until pedal is firm.

Hydraulic Brake System Bleeding Pressure Bleeding

Tools Required

J 35589 Pressure Bleeding Adapter


    Object Number: 171934 Size: SH
  1. Remove the master cylinder reservoir cap. Replace it with J 35589 .
  2. Charge the bleeder to 140-172 kPa (20-25 psi).
  3. Connect the hose to J 35589 .
  4. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

    5. Object Number: 63934 Size: SH
  5. If it is necessary to bleed all of the brake calipers, the following sequence should be used:
    6. 5.1. Right rear
    5.2. Left rear
    5.3. Right front
    5.4. Left front
  6. Place the proper size box end wrench, or equivalent, over the brake caliper bleed screw. Attach a clear tube over the screw and allow the tube to hang submerged in a clear container partially filled with brake fluid.
  7. Open the brake caliper bleed screw at least three quarters of a turn and allow the brake fluid flow to continue until no air is seen in the brake fluid. Apply intermittent pressure to the brake pedal while pressure bleeding.

    8. 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.

  8. Close the brake caliper bleed screw.

    9. Tighten
    Tighten the brake caliper bleed screw to 12 N·m (106 lb in).

  9. Repeat steps 6 through 8 until all of the calipers have been bled.
  10. Lower the vehicle.
  11. Test drive the vehicle, checking for brake pedal for sponginess or softness. Ensure that vehicle exceeds 5 km/h (3 mph) for ABS modulator actuation (self-test) which will purge any air from the secondary circuit of the modulator. If after ABS modulator actuation the pedal is still soft or spongy, then re-bleed entire system.
  12. Remove the brake bleeding equipment from the master cylinder.

Hydraulic Brake System Bleeding When To Bleed

A bleeding operation is necessary to remove air when it is introduced into the hydraulic brake system.

It may be necessary to bleed the hydraulic system at all four corners if air has been introduced through low fluid level or by disconnecting brake pipes at the master cylinder. If a brake hose is disconnected at one wheel, only that wheel caliper needs to be bled. If brake pipes or hoses are disconnected at any fitting located between master cylinder and brakes, then the brake system served by the disconnected pipe or hose must be bled.