Hydraulic Brake System Bleeding (Delco VI)

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.

CAUTION: Use only SUPREME 11 (GM P/N# 12377967) DOT 3 brake fluid from a clean, sealed container. Do not use fluid from an open container that may be contaminated with water. Improper or contaminated fluid could result in damage to components, or loss of braking, with possible injury.

CAUTION: Do not overfill the brake fluid reservoir. Overfilling the brake fluid reservoir may cause the brake fluid to overflow onto the engine exhaust components during brake system service. The brake fluid is flammable and may cause a fire and personal injury if the brake fluid contacts the engine exhaust system components.

NOTICE: If any brake component is repaired or replaced such that air is allowed to enter the brake system, the entire bleeding procedure must be followed.

NOTICE: Avoid spilling brake fluid on any of the vehicle's painted surfaces, wiring, cables or electrical connectors. Brake fluid will damage paint and electrical connections. If any fluid is spilled on the vehicle, immediately flush the area with water to minimize the potential for damage.

NOTICE: Prior to bleeding the brakes, 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 is extremely important that the procedure be followed exactly as outlined.

A bleeding operation is necessary in order to remove air when air is introduced into the hydraulic brake system.
Bleed the hydraulic system at all four brakes if air has been introduced through a low fluid level or by disconnecting the brake pipes at the master cylinder. If a brake hose or brake pipe is disconnected at one wheel, bleed only that one wheel caliper. If brake pipes or hoses are disconnected at any fitting located between the master cylinder and the brakes, then bleed the brake system served by the disconnected pipe or hose.

WITH SCAN TOOL (PREFERRED METHOD)
1. Using a Scan Tool, select the Motor Rehome function. The motor rehome function cannot be performed if current DTCs are present. If DTCs are present, then repair the vehicle and clear the DTCs before performing the Motor Rehome function.
2. Bleed the entire brake system using either Pressure Bleeding or Manual Bleeding.

WITHOUT SCAN TOOL

NOTICE: This method can only be used if the amber ABS warning indicator is not illuminated and no DTCs are present.

IMPORTANT: Do not place your foot on the brake pedal through this entire procedure unless specifically directed to do so.

1. Remove your foot from the brake pedal.
2. Start the engine. Allow the engine to run for at least 10 seconds while observing the amber ABS warning indicator.
3. If the amber ABS warning indicator turns on and stays on after about 10 seconds, stop the bleeding procedure and use a Scan Tool in order to diagnose the ABS malfunction.
4. If the amber ABS warning indicator turns on for approximately 3 seconds, then turns off and stays off, turn the ignition off.
5. Repeat Steps 1 through 4 one more time.
6. Bleed the entire brake system.

PRESSURE BLEEDING

- Tools Required
- J29532 Diaphragm Type Brake Bleeder
- J35589 Compact Brake 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, and other contaminants from entering the hydraulic system.

1. Clean the brake fluid reservoir cover and the surrounding area.
2. Remove the brake fluid reservoir cap.
3. Inspect the brake fluid reservoir level.
4. Connect the J35589 to the brake fluid reservoir.
5. Connect the bleeder adapter to the pressure bleeding equipment.
6. Adjust the pressure bleed equipment to 35 - 70 kPa (5 - 10 psi). Wait approximately 30 seconds in order to ensure that there is no leakage.
7. Adjust the pressure bleed equipment to 205 - 240 kPa (30 - 35 psi).

NOTICE: Refer to Fastener Notice in Service Precautions.

IMPORTANT: Use a shop cloth in order to catch escaping brake fluid. Prevent the fluid from running down the motor pack base or into the electrical connector, Also, do not allow brake fluid to contact any painted surfaces as surface damage will occur. If brake fluid does contact any surface, flush the surface with water to lessen the damage.





8. Complete the following procedure with the pressure bleeding equipment connected and pressurized:
8.1. Attach a clear plastic bleeder hose to the rearward bleeder valve on the brake modulator. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
8.2. Slowly open the bleeder valve. Allow the fluid to flow until no air is seen in the fluid.
8.3. Close the valve when the fluid flows without any air bubbles.
8.4. Repeat the previous two steps until no air bubbles are present.
8.5. Relocate the bleeder hose on the forward brake modulator bleeder valve. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
8.6. Slowly open the bleeder valve. Allow the fluid to flow until no air is seen in the fluid.
8.7. Close the valve when fluid flows without any air bubbles.
8.8. Repeat the previous two steps until no air bubbles are present.
- Tighten the ABS modulator bleeder valves to 9 Nm (80 inch lbs.).

9. Bleed the brake modulator brake pipe connections with the pressure bleeding equipment connected and pressurized:
9.1. Slowly open the forward brake pipe tube nut on the brake modulator and check for air in the escaping fluid.
9.2. When the air flow ceases, immediately tighten the tube nut.
- Tighten the tube nut to modulator to 24 Nm (18 ft. lbs.).

9.3. Repeat step 9 for the remaining three brake pipe connections moving from front to rear.

10. Raise and suitably support the vehicle.

IMPORTANT: Bleed sequence:

10.1. Right rear
10.2. Left front
10.3. Left rear
10.4. Right front

11. Bleed the brakes in the following sequence.
12. Bleed the brakes in the sequence shown above.
Complete the following steps:
12.1. Attach a clear plastic bleeder hose to the bleeder valve at the wheel. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
12.2. Slowly open the bleeder valve. Allow the fluid to flow.

IMPORTANT: Ensure that the bleeder valves do not leak.

12.3. Close the valve when the fluid begins to flow without any air bubbles. Tap lightly on the caliper or backing plate in order to dislodge any trapped air bubbles.
- Tighten the front caliper bleeder valves to 13 Nm (115 inch lbs.).
- Tighten rear caliper bleeder valves to 7 Nm (62 inch lbs.).
- Tighten the rear wheel cylinder bleeder valves to 7 Nm (62 inch lbs.).

13. Remove the pressure bleeding equipment, including the J35589.
14. Lower the vehicle.
15. Inspect the brake fluid level in the reservoir. Fill the reservoir to the proper level if necessary.
16. Reinstall the brake fluid reservoir cap.
16.1. Turn the ignition to the RUN position, then turn off the engine. Apply the brake pedal with moderate force and hold. Note the pedal travel and feel.
16.2. If the pedal feels firm and constant, and pedal travel is not excessive, start the engine. With the engine running, re-check the pedal travel. If the pedal travel is still firm and constant and pedal travel is not excessive perform a road test on the vehicle. Make several normal (non-ABS) stops from a moderate speed in order to ensure proper brake system function. Allow adequate cooling time between stops.
16.3. If the pedal feels soft or has excessive travel either initially or after the engine starts, use the following procedure.
16.3.1. With the Scan Tool, release then apply each motor 2-3 time and cycle each solenoid 5-10 times.
16.3.2. When finished, be sure to apply the front and rear motors in order to ensure the pistons are in the upmost position. DO NOT DRIVE THE VEHICLE.
16.3.3. If a Scan Tool is not available, remove your foot from the brake pedal, start the engine and allow it to run for at least 10 seconds to initialize the ABS.
DO NOT DRIVE THE VEHICLE.
16.3.4. After 10 seconds, turn the ignition off.
16.3.5. Repeat this initialization procedure 5 time in order to ensure that any trapped air has been dislodged. Repeat this pressure bleeding procedure starting at Step 1.

16.4. Perform a road test on the vehicle. Make several normal (non-ABS) stops from a moderate speed in order to ensure proper brake system function. Allow adequate cooling time between stops.


MANUAL BLEEDING

IMPORTANT: In the following procedure, use a suitable container or shop cloths in order to catch the brake fluid and prevent the fluid from contacting any painted surfaces.





1. Clean the brake fluid reservoir cap and the surrounding area.
2. Remove the brake fluid reservoir cap.
3. Inspect the brake fluid level. Fill the reservoir to the correct level if necessary.
4. Install the brake fluid reservoir cap.

IMPORTANT: Once the fluid is visibly flowing from both modulator bleeder valves, the ABS brake 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 the brakes. This ensures that the lowest points in the system are completely free of air. The ABS brake modulator/master cylinder assembly may then be purged of any remaining air.

5. Prime the ABS brake modulator/master cylinder assembly. Complete the following steps:
5.1. Attach the bleeder hose to the rearward bleeder valve. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
5.2. Slowly open the rearward bleeder valve.
5.3. Depress the brake pedal and hold the pedal until the fluid begins to flow.
5.4. Close the valve and release the brake pedal.
5.5. Repeat the previous three steps until air bubbles are no longer present.
5.6. Relocate the bleeder hose to the forward brake modulator bleeder valve. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
5.7. Slowly open the forward bleeder valve.
5.8. Depress the brake pedal and hold the pedal until the fluid begins to flow.
5.9. Close the valve and release the brake pedal.
5.10. Repeat the previous three steps until air bubbles are no longer present.

6. Remove the brake fluid reservoir cover.
7. Inspect the brake fluid level in the reservoir. Fill the reservoir to the correct level, if necessary.
8. Install the brake fluid reservoir cover.
9. Raise and suitably support the vehicle.

IMPORTANT: Bleed sequence:

9.1. Right rear
9.2. Left front
9.3. Left rear
9.4. Right front

10. Bleed the brakes in the following sequence.
11. Bleed the brakes in the sequence shown above.
Complete the following steps:
11.1. Attach a clear bleeder hose to the bleeder valve at the wheel. Submerge the opposite hose in a clean container partially filled with clean brake fluid.
11.2. Open the bleeder valve.
11.3. Slowly depress the brake pedal.
11.4. Close the valve and slowly release the brake pedal.
11.5. Wait five seconds.

IMPORTANT: In order to assist in freeing the entrapped air, tap lightly on the caliper or braking plate in order to dislodge any trapped air bubbles.

IMPORTANT: Ensure that the bleeder valves do not leak.

11.6. Repeat this entire procedure until the brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose.
- Tighten the front caliper bleeder valves to 13 Nm (l15 inch lbs.).
- Tighten the rear caliper bleeder valves to 7 Nm (62 inch lbs.).
- Tighten the rear wheel cylinder bleeder valves to 7 Nm (62 inch lbs.).

12. Lower the vehicle.
13. Remove the brake fluid reservoir. Fill the reservoir to the correct level if necessary.
14. Install the brake fluid reservoir cap.
15. Bleed the ABS modulator/master cylinder assembly. Complete the following steps:
15.1. Attach a clear plastic bleeder hose to the rearward bleeder valve on the ABS brake modulator. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
15.2. Depress the brake pedal with moderate force.
15.3. Slowly open the rearward bleeder valve and allow the fluid to flow.
15.4. Close the valve and release the brake pedal.
15.5. Wait five seconds.
15.6. Repeat the procedure until air bubbles are no longer visible in the bleeder hose.
15.7. Relocate the bleeder hose on the forward brake modulator bleeder valve. Submerge the opposite hose end in a clean container partially filled with clean brake fluid.
15.8. Depress the brake pedal with moderate force.
15.9. Slowly open the rearward bleeder valve and allow the fluid to flow.
15.10. Close the valve and release the brake pedal.
15.11. Wait five seconds.
15.12. Repeat the procedure until air bubbles are no longer visible in the bleeder hose.

16. Remove the brake fluid cap.
17. Inspect the brake fluid level in the reservoir. Fill to the correct level if necessary.
18. Install the brake fluid reservoir cap.
19. Turn the ignition switch to the RUN position, then turn off the engine. Apply the brake pedal with moderate force and hold. Note the pedal travel and feel.
20. If the pedal feels firm and constant, and pedal travel is not excessive, start the engine. With the engine running, recheck the pedal travel. If the pedal feel is still firm and constant and pedal travel is not excessive, perform a road test on the vehicle. Make several normal (non-ABS) stops from a moderate speed in order to ensure proper brake system function.
21. If pedal feel is soft or has excessive travel either initially or after engine start, use the following procedure:
21.1. Using the Scan Tool, release then apply each motor 2-3 times and cycle each solenoid 5-10 times.
21.2. Apply the front and rear motors in order to ensure that the pistons are in the upmost position. DO NOT DRIVE THE VEHICLE.
21.3. If a Scan Tool is not available, remove your foot from the brake pedal, then start the engine. Allow the engine to run for at least 10 seconds in order to initialize the ABS. DO NOT DRIVE THE VEHICLE.
21.4. After 10 seconds, turn off the ignition.

22. Repeat the initialization procedure five times in order to dislodge any air in the system.
23. Repeat this manual bleeding procedure, starting at Step 1.
24. Perform a vehicle road test. Make several normal (non-ABS) stops from a moderate speed in order to ensure proper brake system function.