GM Lumina/Grand Prix/Cutlass Supreme/Regal 1988-1996

System Bleeding

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If the hydraulic unit has been replaced, or if air has entered the brake lines, the entire brake system (hydraulic unit, lines and calipers) must be bled at each wheel.

If only a hydraulic part of the hydraulic unit has been replaced (bleeder valve, tube and nut assembly, accumulator, reservoir, solenoid, or pressure switch), and no air has entered the brake lines, it may only be necessary to bleed the hydraulic unit by performing an ABS solenoid bleed and checkout test using a hand scanner tool or by bleeding the booster section of the hydraulic unit at its bleeder valves. Neither performing an ABS solenoid bleed and checkout test nor bleeding the hydraulic unit at its bleeder valves will remove air from the brake lines.

PRESSURE BLEEDING



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.

Use only DOT 3 brake fluid from a sealed container. Do not use any suspect or contaminated fluid. Do not use DOT 5 silicone fluid.

  1. Depressurize the hydraulic unit before pressure bleeding.
  2.  

Make sure the vehicle ignition switch is OFF, unless otherwise noted. This will prevent the hydraulic unit pump from starting during the bleeding procedure.

  1. Clean the reservoir cover and diaphragm assembly, then remove the cover.
  2.  
  3. Check the fluid level in both the reservoir sections and fill to the correct level using clean brake fluid, if necessary.
  4.  
  5. Install the bleeder adapter J-37115 or equivalent and secure with attachment cable. Make sure attachment cable does not interfere with access to the bleeder valves on the hydraulic unit.
  6.  
  7. Attach the adapter to the pressure bleed equipment and charge to 5-10 psi (34.5-69 kPa) for approximately 30 seconds. If no leaks exist, slowly increase the pressure to 30-35 psi (207-241 kPa). 20-25 psi (138241 kPa) is acceptable but not preferred.
  8.  
  9. Bleed the adapter; place a rag over the valve to absorb vented fluid. Depress ball to open the bleeder valve; continue until fluid flows without air.
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  11. Raise and safely support the vehicle.
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  13. Bleed individual wheel brakes in this sequence: right rear, left rear, right front and left front.
    1. Attach the bleeder hose to the bleeder valve and submerge the opposite end in a clean container partially filled with fresh brake fluid.
    2.  
    3. Slowly open the bleeder valve and allow the fluid to flow until no air is seen in the fluid.
    4.  
    5. Allow the brake fluid to flow for at least 20-30 seconds at each wheel when checking for trapped air.
    6.  
    7. To assist in freeing trapped air, tap lightly on the caliper castings with a rubber mallet.
    8.  
    9. Close the valve when the fluid begins to flow without any air bubbles.
    10.  

  14.  
  15. Lower the vehicle.
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  17. Bleed the Powermaster III isolation valves.
    1. Attach the bleeder hose to the bleeder valve on the inboard side of the Powermaster III and submerge the opposite end in a container partially filled with fresh brake fluid.
    2.  
    3. Slowly open the bleeder valve and allow the fluid to flow until no air is seen in the fluid.
    4.  
    5. Close the valve when the fluid begins to flow without any air bubbles.
    6.  
    7. Repeat the procedure on the outboard side of the bleeder valve.
    8.  

  18.  
  19. Remove the bleeder adapter J-37115 from the hydraulic unit.
  20.  
  21. Check the fluid level in both the reservoir chambers. Using clean brake fluid, fill the reservoirs to the proper level, if necessary.
  22.  
  23. Replace the reservoir cover and snap all 4 cover tabs in place on the reservoir.
  24.  
  25. Apply brake pedal 3 times with sharp, jabbing applications.
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  27. Bleed the booster section of the Powermaster III.
    1. If scanner 094-00101 or equivalent, is available connect it. Turn the ignition to ON and allow the pump to pressurize the accumulator. When the pump stops, use the scanner to perform the "Solenoid Bleed and Check Test''.
    2.  
    3. If a scanner is not available, depress the brake pedal with moderate pressure and turn the key to ON without starting the motor for 3 seconds. Repeat this OFF / ON cycle 10 times to cycle the solenoids.
    4.  

  28.  
  29. Bleed the accumulator. Do not check brake fluid level without depressurizing the Powermaster III; overfilling may result. After depressurizing, wait 2 minutes before checking level; this will allow air to clear from the brake fluid.
  30.  
  31. Turn the ignition to ON without starting the engine; allow the system to pressurize. Check brake pedal for correct feel and travel.
  32.  
  33. Road test the vehicle.
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MANUAL BLEEDING



  1. Depressurize the hydraulic unit before pressure bleeding.
  2.  

Make sure the vehicle ignition switch is OFF, unless otherwise noted. This will prevent the hydraulic unit pump from starting during the bleeding procedure.

  1. Clean the reservoir cover and diaphragm assembly; then remove the assembly.
  2.  
  3. Check the fluid level in both the reservoir sections and fill to the correct level using clean brake fluid, if necessary.
  4.  
  5. Raise the vehicle and support safely.
  6.  
  7. Bleed the right front wheel brake.
    1. Attach a bleeder hose to the bleeder valve and submerge the opposite end in a clean container partially filled with brake fluid.
    2.  
    3. Open the bleeder valve.
    4.  
    5. Slowly depress the brake pedal.
    6.  
    7. To assist in freeing entrapped air, tap lightly on the caliper with a rubber mallet.
    8.  
    9. Close the valve and release the brake pedal.
    10.  
    11. Check the fluid level and add new brake fluid, if necessary.
    12.  

  8.  
  9. Repeat Step 5 until the brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose.
  10.  
  11. Repeat Steps 5 and 6 on the left front wheel brake.
  12.  
  13. Turn the ignition switch ON and allow the pump motor to run. (Shut ignition switch OFF if the pump runs for more than 60 seconds; check the hydraulic system.)
  14.  
  15. Bleed the right rear wheel brake.
    1. Attach a bleeder hose to the bleeder valve and submerge the opposite end in a clean container partially filled with brake fluid.
    2.  
    3. Open the bleeder valve.
    4.  
    5. With the ignition switch ON , slowly depress the brake pedal part way, until the brake fluid begins to flow from the bleeder hose. Hold for 15 seconds. Do NOT fully depress the brake pedal.
    6.  
    7. To assist in freeing entrapped air, tap lightly on the caliper castings with a rubber mallet.
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    9. Close the valve and release the brake pedal.
    10.  
    11. Repeat these steps until no air bubbles are observed in the bleeder hose.
    12.  
    13. Check the fluid level and add new brake fluid, if necessary. Turn the ignition OFF and depressurize the hydraulic unit before checking the fluid level.
    14.  

  16.  
  17. Repeat Steps 8 and 9 on the left rear wheel brake.
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  19. Lower the vehicle.
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  21. Bleed the Powermaster III isolation valves.
    1. Attach the bleeder hose to the bleeder valve on the inboard side of the Powermaster III and submerge the opposite end in a container partially filled with fresh brake fluid.
    2.  
    3. Slowly open the bleeder valve and allow the fluid to flow until no air is seen in the fluid.
    4.  
    5. Close the valve when the fluid begins to flow without any air bubbles.
    6.  
    7. Repeat the procedure on the outboard side of the bleeder valve.
    8.  

  22.  

This step can also be performed using a scanner.

  1. Bleed the hydraulic unit solenoids. This step will insure that the brake pedal applies firmly and smoothly.
    1. Apply moderate force on the brake pedal.
    2.  
    3. With the pedal applied, turn the ignition switch ON for 3 seconds, then turn OFF . Do this 10 times in succession to cycle the solenoids Do not start the engine.
    4.  

  2.  
  3. Depressurize the hydraulic unit and wait 2 minutes for the air to clear from within the reservoir.
  4.  
  5. Bleed the hydraulic unit of air accumulated from the solenoids.
    1. Attach the bleeder hose to the bleeder valve on the inboard side of the hydraulic unit and submerge the opposite end in a clean container partially filled with fresh brake fluid.
    2.  
    3. With the ignition switch ON , apply light force to the brake pedal.
    4.  
    5. With the pedal applied, slowly open the bleeder valve and allow the fluid to flow until no air is seen in the fluid.
    6.  
    7. Close the valve when the fluid begins to flow without any air bubbles.
    8.  
    9. Repeat the procedure on the outboard side of the hydraulic unit.
    10.  

  6.  
  7. Turn the ignition switch OFF , depressurize the hydraulic unit.
  8.  
  9. Remove the reservoir cover and diaphragm assembly.
  10.  
  11. Check the fluid level in both reservoir sections. Using clean brake fluid, fill the reservoirs to their proper level, if necessary.
  12.  
  13. Install the reservoir cover and snap all 4 tabs in place on the reservoir.
  14.  
  15. Turn the ignition switch ON and allow the pump motor to run. Shut the ignition switch OFF if the pump motor runs for more than 60 seconds; check the hydraulic system.
  16.  
  17. Apply the brake pedal noting feel and travel. If feel is firm, smooth and without excess pedal travel, vehicle is ready for road testing. If pedal feel is soft, spongy or has excessive pedal travel re-bleed the front brakes. If conditions still exist, perform Preliminary Inspection. Depressurize Powermaster III and recheck fluid level.
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