Log In
Search suggestions

    My Vehicles

    1990 Geo Prizm 1.6L MFI DOHC 4cyl

    My Store

    1720 S RIDGEWOOD A
    (386) 427-1210

    OPEN 'til 9:00 PM today

    GET A $25 GIFT CARD FOR EVERY $100 SPENT ON ONLINE SHIP-TO-HOME ORDERS.

    Use Code: GIFTME

    See Details

    Alero, Grand Am 1999-2005

    Bleeding the ABS System

    Print

    Before bleeding the ABS brake system, the front and rear displacement cylinder pistons must be returned to the topmost position. The preferred method uses a scan tool to perform the rehoming procedure. If a scan tool is not available, the second procedure may be used, but it must be followed exactly.

    Automated Bleed Procedure



    1. Perform a manual or pressure bleeding procedure.. If the desired brake pedal height results are not achieved, perform the automated bleed procedure below.
    2.  

    The procedure cycles the system valves and runs the pump in order to purge the air from the secondary circuits normally closed off during normal base brake operation and bleeding. The automated bleed procedure is recommended when air ingestion is suspected in the secondary circuits, or when the BPMV has been replaced.


    NOTE
    The Auto Bleed Procedure may be terminated at any time during the process by pressing the EXIT button. No further Scan Tool prompts pertaining to the Auto Bleed procedure will be given. After exiting the bleed procedure, relieve bleed pressure and disconnect bleed equipment per manufacturers instructions.


    WARNING
    Failure to properly relieve pressure may result in spilled brake fluid causing damage to components and painted surfaces.

    1. Raise the vehicle on a suitable support.
    2.  
    3. Remove all four tire and wheel assemblies.
    4.  
    5. Inspect the brake system for leaks and visual damage.
    6.  
    7. Inspect the battery state of charge.
    8.  
    9. Install a scan tool.
    10.  
    11. Turn ON the ignition, with the engine OFF .
    12.  
    13. With the scan tool, establish communications with the EBCM. Select Special Functions. Select Automated Bleed from the Special Functions menu.
    14.  
    15. Bleed the base brake system.
    16.  
    17. Follow the scan tool directions until the desired brake pedal height is achieved.
    18.  
    19. If the bleed procedure is aborted, a malfunction exists. Perform the following steps before resuming the bleed procedure:
      1. If a DTC is detected, diagnose the appropriate DTC.
      2.  
      3. If the brake pedal feels spongy, perform the conventional brake bleed procedure again.
      4.  

    20.  
    21. When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
    22.  
    23. Remove the scan tool.
    24.  
    25. Install the tire and wheel assemblies.
    26.  
    27. Inspect the brake fluid level.
    28.  
    29. Road test the vehicle while inspecting that the pedal remains high and firm.
    30.  

    Manual Bleeding



    1. Clean the master cylinder fluid reservoir cover and surrounding area, then remove the cover.
    2.  
    3. Add fluid, if necessary to obtain a proper fluid level, then put the reservoir cover back on.
    4.  
    5. Prime the ABS hydraulic modulator/master cylinder assembly as follows:
      1. Attach a bleeder hose to the rearward bleeder valve, then submerge the opposite hose end in a clean container partially filled with clean brake fluid.
      2.  
      3. Slowly open the rearward bleeder valve.
      4.  
      5. Depress and hold the brake pedal until the fluid begins to flow.
      6.  
      7. Close the valve, then release the brake pedal.
      8.  
      9. Repeat Steps 3b-3d until no air bubbles are present.
      10.  
      11. Relocate the bleeder hose to the forward hydraulic modulator bleeder valve, then repeat Steps 3a-3e.

        Click image to see an enlarged view

        Fig. ABS hydraulic modulator/master cylinder bleeder locations

      12.  

    6.  
    7. Once the fluid is seen to flow from both modulator bleeder valves, the ABS modulator/master cylinder assembly is sufficiently full of fluid. However, it may not be completely purged of air. At this point, move to the wheel brakes and bleed them. This ensures that the lowest points in the system are completely free of air and then the assembly can purged of any remaining air.
    8.  
    9. Remove the fluid reservoir cover. Fill to the correct level, if necessary, then fasten the cover.
    10.  
    11. Raise and safely support the vehicle.
    12.  
    13. Proceed, as outlined in the following steps, to bleed the wheel brakes in the following sequence: right rear, left rear, right front, then left front.
      1. Attach a clear plastic bleeder hose to the bleeder valve at the wheel, then submerge the opposite hose end in a clean container partially filled with clean brake fluid.
      2.  
      3. Open the bleeder valve.
      4.  
      5. Have an assistant slowly depress the brake pedal.
      6.  
      7. Close the valve and slowly release the release the brake pedal.
      8.  
      9. Wait 5 seconds.
      10.  
      11. Repeat Steps 7a-7e until the brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose. To assist in freeing the entrapped air, tap lightly on the caliper or braking plate to dislodge any trapped air bubbles.
      12.  

    14.  
    15. Repeat Step 7 for the remaining brakes in the sequence given earlier.
    16.  
    17. Carefully lower the vehicle.
    18.  
    19. Remove the reservoir cover, then fill to the correct level with brake fluid and replace the cap.
    20.  
    21. Bleed the ABS hydraulic modulator/master cylinder assembly as follows:
      1. Attach a clear plastic bleeder hose to the rearward bleeder valve on the modulator, then submerge the opposite hose end in a clean container partially filled with clean brake fluid.
      2.  
      3. Have an assistant depress the brake pedal with moderate force.
      4.  
      5. Slowly open the rearward bleeder valve and allow the fluid to flow.
      6.  
      7. Close the valve, then release the brake pedal.
      8.  
      9. Wait 5 seconds.
      10.  
      11. Repeat Steps 11a-11e until no air bubbles are present.
      12.  
      13. Relocate the bleeder hose to the forward hydraulic modulator bleeder valve, then repeat Steps 11a-11f.
      14.  

    22.  
    23. Carefully lower the vehicle, then check the brake fluid and add if necessary. Don't forget to put the reservoir cap back on.
    24.  
    25. With the ignition turned to the RUN position, apply the brake pedal with moderate force and hold it. Note the pedal travel and feel. If the pedal feels firm and constant and the pedal travel is not excessive, start the engine. With the engine running, recheck the pedal travel. If it's still firm and constant and pedal travel is not excessive, go to Step 17.
    26.  
    27. If the pedal feels soft or has excessive travel either initially or after the engine is started, the following procedure may be used:
      1. With the Tech 1 scan tool, -Release'' then -Apply'' each motor 2-3 times and cycle each solenoid 5-10 times. When finished, be sure to -Apply'' the front and rear motors to ensure the pistons are in the upmost position. DO NOT DRIVE THE VEHICLE.
      2.  
      3. If a Tech 1 scan tool is not available, remove your foot from the brake pedal, start the engine and allow it run for at least 10 seconds to initialize the ABS. DO NOT DRIVE THE VEHICLE. After 10 seconds, turn the ignition OFF . The initialization procedure most be repeated 5 times to ensure any trapped air has been dislodged.
      4.  
      5. Repeat the bleeding procedure, starting with Step 1.
      6.  

    28.  
    29. Road test the vehicle, and make sure the brakes are operating properly.
    30.  

    Pressure Bleeding




    NOTE
    The 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 and other contaminants from entering the hydraulic system.

    1. Remove the battery tray.
    2.  
    3. Clean the master cylinder fluid reservoir cover and surrounding area, then remove the cover.
    4.  
    5. Add fluid, if necessary to obtain a proper fluid level.
    6.  
    7. Connect bleeder adapter J 35589, or equivalent, to the brake fluid reservoir, then connect the bleeder adapter to the pressure bleeding equipment.
    8.  
    9. Adjust the pressure bleed equipment t o 5-10 psi (35-70 kPa) and wait about 30 seconds to be sure there is no leakage.
    10.  
    11. Adjust the pressure bleed equipment to 30-35 psi (205-240 kPa).
      WARNING
      Use a shop rag to catch the escaping brake fluid. Be careful not to let any fluid run down the motor pack base or into the electrical connector.



      Click image to see an enlarged view

      Fig. ABS pressure bleeding procedure



      Click image to see an enlarged view

      Fig. Position a shop rag to catch escaping brake fluid

    12.  
    13. With the pressure bleeding equipment connected and pressurized, proceed as follows:
      1. Attach a clear plastic bleeder hose to the rearward bleeder valve on the hydraulic modulator.
      2.  
      3. Slowly open the bleeder valve and allow fluid to flow until no air is seen in the fluid.
      4.  
      5. Close the valve when fluid flows out without any air bubbles.
      6.  
      7. Repeat Steps 6b and 6c until no air bubbles are present.
      8.  
      9. Relocate the bleeder hose on the forward hydraulic modulator bleed valve and repeat Steps 6a through 6d.
      10.  

    14.  
    15. Tighten the bleeder valve to 80 inch lbs. (9 Nm).
    16.  
    17. Proceed to bleed the hydraulic modulator brake pipe connections as follows with the pressure bleeding equipment connected and pressurized:
      1. Slowly open the forward brake pipe tube nut on the hydraulic modulator and check for air in the escaping fluid.
      2.  
      3. When the air flow ceases, immediately tighten the tube nut. Tighten the tube nut to 18 ft. lbs. (24 Nm).
      4.  

    18.  
    19. Repeat Steps 8a and 8b for the remaining three brake pipe connections moving from the front to the rear.
    20.  
    21. Raise and safely support the vehicle.
    22.  
    23. Proceed, as outlined in the following steps, to bleed the wheel brakes in the following sequence: right rear, left rear, right front, then left front.
      1. Attach a clear plastic bleeder hose to the bleeder valve at the wheel, then submerge the opposite hose end in a clean container partially filled with clean brake fluid.
      2.  
      3. Slowly open the bleeder valve and allow the fluid to flow.
      4.  
      5. Close the valve when fluid begins to flow without any air bubbles. Tap lightly on the caliper or backing plate to dislodge any trapped air bubbles.
      6.  

    24.  
    25. Repeat Step 11 on the other brakes using the earlier sequence.
    26.  
    27. Remove the pressure bleeding equipment, including bleeder adapter J 35589.
    28.  
    29. Carefully lower the vehicle, then check the brake fluid and add if necessary. Don't forget to put the reservoir cap back on.
    30.  
    31. With the ignition turned to the RUN position, apply the brake pedal with moderate force and hold it. Note the pedal travel and feel. If the pedal feels firm and constant and the pedal travel is not excessive, start the engine. With the engine running, recheck the pedal travel. If it's still firm and constant and pedal travel is not excessive, go to Step 17.
    32.  
    33. If the pedal feels soft or has excessive travel either initially or after the engine is started, the following procedure may be used:
      1. With the Tech 1 scan tool, -release'' then -apply'' each motor 2-3 times and cycle each solenoid 5-10 times. When finished, be sure to -apply'' the front and rear motors to ensure the pistons are in the upmost position. DO NOT DRIVE THE VEHICLE.
      2.  
      3. If a Tech 1 is not available, remove your foot from the brake pedal, start the engine and allow it run for at least 10 seconds to initialize the ABS. DO NOT DRIVE THE VEHICLE. After 10 seconds, turn the ignition -OFF''. The initialization procedure most be repeated 5 times to ensure any trapped air has been dislodged.
      4.  
      5. Repeat the bleeding procedure, starting with Step 1.
      6.  

    34.  
    35. Road test the vehicle, and make sure the brakes are operating properly.
    36.  

    Rehome Procedure



    With Scan Tool (Preferred Method)
    1. Using a scan tool, select the Motor Rehome Function'. The motor rehome function cannot be performed if current DTC's are present. If DTC's are present, the vehicle must be repaired and the codes cleared before performing the motor rehome function.
    2.  
    3. The entire brake system should now be bled using the pressure or manual bleeding procedures outlined later in this section.
    4.  

    Without Scan Tool

    NOTE
    Do not place your foot on the brake pedal through this entire procedure unless specifically instructed to do so.


    WARNING
    This method can only be used if the ABS warning lamp is not illuminated and no DTC's are present.

    1. Remove your foot from the brake pedal.
    2.  
    3. Start the engine and allow it to run for at least 10 seconds while observing the ABS warning lamp.
    4.  
    5. If the ABS warning lamp turned -ON'' and stayed -ON'' after about 10 seconds, the bleeding procedure must be stopped and a scan tool must be used to diagnose the ABS function.
    6.  
    7. If the ABS warning lamp turned -ON'' for about 3 seconds, then turned -OFF'' and stayed -OFF'', turn the ignition -OFF''.
    8.  
    9. Repeat Steps 1-4 one more time.
    10.  
    11. The entire brake system should now be bled following the manual or pressure bleeding procedure.
    12.  

     
    AutoZone Logo