Antilock Brakes / Traction Control Systems: Service and Repair

WARNING: Do not drive the vehicle until brake pedal feel is firm.

CAUTION: Do not re-use brake fluid used during bleeding.

NOTE: The two-person bleed procedure is required when installing a new electro-hydraulic control unit, or when air is suspected to be trapped in the valve body. Vacuum, pressure, or gravity bleeding may be used for base brake bleeding only.

TWO PERSON PROCEDURE
1. Raise and support the vehicle to gain access to the system bleed screws.
2. Begin by bleeding the system at the right rear wheel.
3. Install clear hose on the bleed screw. Immerse the opposite end of the hose into a container partially filled with clean DOT 3 brake fluid.
4. Open the bleed screw 1/2 to 1 full turn.
5. Slowly depress the brake pedal until it reaches its full travel and hold until the bleed screw has been tightened. Release the brake pedal and wait 10-15 seconds for the master cylinder pistons to return to the home position.
6. Repeat Steps 3 through 5 on the left rear, then right front, then left front, until clean, air free brake fluid is present at each of the wheel bleed screws. This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every 4 to 6 strokes of the brake pedal to avoid running the system dry.
7. If the Brake Pressure Modulator Valve (BPMV) has been replaced, or suspected of containing air, Use a Scan Tool to run Function Test four times consecutively while applying the brake pedal firmly. Remove foot from the brake pedal between each test.
8. Rebleed all four wheels using Steps 3 through 5 to remove the remaining air from the brake system.
9. Evaluate the brake pedal feel before attempting to drive the vehicle and re-bleed as many times as necessary to obtain appropriate pedal feel.