ABS Bleeding

CAUTION: Use only Delco Supreme 11(R) Brake Fluid, GM PIN 1052542, or equivalent 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 personal injury.

NOTE: 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.

Motor Rehome Procedure
1. Using a Tech 2 scan tool, select Motor Rehome under Special Functions. The motor rehome function cannot be performed if current DTCs are present. If DTCs are present, the vehicle must be repaired and DTCs cleared before performing the motor rehome function.
2. The entire brake system should now be bled following either the manual bleeding procedure or pressure bleeding procedure.Manual Bleeding

BLEEDING PROCEDURE
^ Clean Master cylinder reservoir cap and surrounding area.
1. Remove master cylinder reservoir cap.

^ Inspect Brake fluid level in reservoir and fill to the correct level if necessary. Make sure to replace the master cylinder reservoir cap.

Bleeding Wheel Cylinder/Caliper (Typical):

2. Prime hydraulic modulator as follows:
A. Attach a clear plastic bleed hose to the rearward bleeder valve on the hydraulic modulator. Submerge the other end of the bleeder hose in a clean container partially filled with brake fluid.
B. Slowly open the bleeder valve 1/2 to 3/4 turn.
C. Have an assistant depress the brake pedal and hold until fluid begins to flow.
D. Close the bleeder valve and release the brake pedal. Repeat steps B through D until no air bubbles are present.
E. Relocate the bleeder hose on the forward hydraulic modulator bleeder valve and repeat steps B through D.
NOTE: Once fluid is seen to flow from both hydraulic modulator bleeder valves, s the hydraulic modulator is sufficiently full of brake fluid. However, it may not be completely purged of air. At, this point, move to the wheel cylinders/calipers and bleed them. This ensures that the lowest points in the system are completely free of air and then the hydraulic modulator can be purged of-any remaining air.

Inspect: Brake fluid level in reservoir and fill to the correct level if necessary. Make sure to replace the master cylinder reservoir cap.

3. Raise and suitably support vehicle. Refer to General Vehicle Lifting and Jacking in General Information.

Bleed wheel cylinders/calipers in the following sequence:
1). Right rear
2). Left rear
3). Right front
4). Left front

4. Bleed wheel cylinders/calipers.
A. Attach a clear plastic bleeder hose to the bleeder valve on the wheel cylinder/caliper. Submerge the other end of the bleeder hose in a clean container partially filled with brake fluid.
B. Open the bleeder valve.
C. Have an assistant slowly depress the brake pedal.
D. Close the bleeder valve and release the brake pedal.
E. Wait five seconds.
F. Repeat steps B through E (including the five second waiting period) until the brake pedal feels firm and no air-bubbles are observed in the bleeder hose.
G. Repeat steps A through F for the remaining wheel cylinder and calipers.

^ Tighten Bleeder valve to 9 Nm (80 inch lbs.).

5. Lower vehicle.

Inspect Brake fluid level tin reservoir and fill to the correct level if necessary. Make sure to replace the master cylinder reservoir cap.

6. Bleed hydraulic modulator:
A. Attach a clear plastic bleeder hose to the rearward bleeder valve on the hydraulic modulator. Submerge the other end of the bleeder hose in a clean container partially filled with brake fluid.
B. Have an assistant depress the brake pedal with moderate force.
C. Slowly open the bleeder valve 1/2 to 3/4 turn and allow fluid to flow
D. Close bleeder valve and release brake pedal.
E. Wait five-seconds.
F. Repeat steps B through E (including the five second waiting period) until all the air is purged from the system.
G. Relocate the bleeder hose on the forward hydraulic modulator bleeder valve and repeat steps B through F.

^ Tighten Bleeder valve to 9 Nm (80 inch lbs.).

Inspect: Brake fluid level in reservoir and fill to the correct level if necessary. Make sure to replace the master cylinder reservoir cap.

7. With the ignition switch in ON, depress the brake pedal with moderate force and hold in position. Note pedal travel and feel.
^ If pedal feels firm and constant and pedal travel is not excessive, do following procedure:

A. Start the engine.
B. Carefully drive vehicle at 10 km/h (6 mph) for 5 seconds.
C. Stop vehicle.
D. Turn ignition switch to LOCK.
E. Repeat steps A through D one more time.

^ Recheck the pedal travel. If it is still firm and constant and pedal travel is not excessive, proceed with step 8.
^ If pedal feels soft or has excessive travel either initially or after engine start, using a Tech 2 scan tool, Release then Apply the motors three times and cycle the solenoids 10 times. Be sure to Apply the motors to ensure that the pistons are in the home position. DO NOT DRIVE THE VEHICLE. Repeat the entire bleeding procedure.

8. Road test the vehicle. Make several normal (non ABS) stops from a moderate speed to ensure proper brake system function. Allow adequate cooling time between stops.