Tool Required

J 21472 Brake Bleeder Wrench

Notice: When filling the master cylinder, use only Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT 3 brake fluid. Do not use a container which has been used for petroleum based fluids, or a container which is wet with water. Petroleum based fluids will cause swelling and distortion of rubber parts in the hydraulic brake system, and water will mix with brake fluid, lowering the boiling point. Keep all fluid containers capped to prevent contamination.

1. Apply the brakes several times with the engine off to remove the vacuum reserve.
2. Use brake fluid to fill the master cylinder reservoir. Ensure to keep the master cylinder reservoir at least half full during the bleeding operation.
3. Perform the following steps if the master cylinder is known or suspected to have air in the bore:

3.1.	Disconnect the front Electronic Brake Traction Control Module (EBTCM) pipe fitting at the master cylinder.

3.2.	Allow the fluid to fill the master cylinder body bore until it begins to flow from the front Electronic Brake Traction Control Module (EBTCM) pipe fitting port.

3.3.	Connect the front Electronic Brake Traction Control Module (EBTCM) pipe to the master cylinder.

3.4.	Tighten the Electronic Brake Traction Control Module (EBTCM) pipe to the master cylinder.

3.5.	Have a helper depress the brake pedal slowly one time and hold.

3.6.	Loosen the front Electronic Brake Traction Control Module (EBTCM) pipe fitting at the master cylinder body to purge the air from the bore.

3.7.	Tighten the fitting.

3.8.	Have the helper slowly release the brake pedal.

3.9.	Wait 15 seconds.

3.10.

Repeat above sequence, including the 15 second wait, until all the air removes from the brake master cylinder body bore. Ensure to prevent fluid from contacting any painted surface.

Tighten
Tighten the brake master cylinder pipe fitting to 16 N·m (12 lb ft).

3.11.

Repeat the procedure outlined above to bleed the master cylinder at the rear Electronic Brake Traction Control Module (EBTCM) fitting after all the air is removed at the front Electronic Brake Traction Control Module (EBTCM) pipe fitting.

Tighten
Tighten the brake master cylinder pipe fitting to 16 N·m (12 lb ft).




4. Bleed the individual front and/or rear brake calipers only after all the air is removed from the brake master cylinder.
5. Follow this sequence if it is necessary to bleed all of the front and rear wheel brake calipers:

5.1.	Right rear.

5.2.	Left rear.

5.3.	Right front.

5.4.	Left front.

6. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
7. Place a proper size box end wrench over the bleeder valve.
8. Attach a clear tube over the front or the rear brake caliper bleeder valve.
9. Allow the tube to hang submerged in a clear container partially filled with brake fluid.
10. Have a helper depress the brake pedal slowly one time and hold.
11. Loosen the bleeder valve to purge the air from the front or the rear caliper.
12. Tighten the front or the rear caliper bleeder valve.
13. Have the helper slowly release the brake pedal.
14. Wait 15 seconds.
15. Repeat the sequence, including the 15 second wait, until all the air removes. It may be necessary to repeat the sequence ten or more times to remove all the air.

Tighten
Tighten the front or the rear brake caliper bleeder valve to 9 N·m (80 lb in).

16. Note that rapid pumping of the brake pedal pushes the master cylinder secondary piston down the master cylinder body bore. This makes it difficult to bleed the rear side of the system.
17. Lower the vehicle.
18. Fill the master cylinder reservoir to the proper level.
19. Inspect for the following conditions:

•	Check the brake pedal for sponginess.

•	Check the red BRAKE indicator lamp for indication of unbalanced pressure.

20. Repeat the entire bleeding procedure to correct either of the two above conditions.