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brake line for chevy avalanche


All of your brake lines run under the driver side on the frame rail.That unit with all of the brake lines is called the Electronic Brake Control Module (EBCM) or ABS unit.

  1. Remove the EBCM (2) from the BPMV (3). Removal may require a light amount of force.

    Click image to see an enlarged view

    Fig. Brake Pressure Modulator Valve (BPMV)-exploded view

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Remove the mounting screws (1) that fasten the EBCM (2) to the brake pressure modulator valve (BPMV) (3).

Click image to see an enlarged view

Fig. Exploded view of EBCM and BPMV

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  1. Disconnect the negative battery cable.
  2. Remove the four T-25 TORX® screws that fasten the EBCM to the BPMV.
    WARNING
    Do not use a tool to pry the EBCM or the BPMV. Excessive force will damage the EBCM.

  3. Partially remove the EBCM from the BPMV enough to access the electrical connectors. Removal may require a light amount of force.
  4. Disconnect the four electrical connectors from EBCM.
  5. Fully remove the EBCM from the BPMV.

    Click image to see an enlarged view

    Fig. Location of EBCM (Electronic Brake Control Module)



    Click image to see an enlarged view

    Fig. Removing Electronic Brake Control Module (EBCM) from Brake Pressure Modulator Valve (BPMV)

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Brake pressure modulator valve (BPMV) - The BPMV uses a 3-circuit configuration to control the left front wheel, the right front wheel, and the combined rear wheels. The BPMV directs fluid to the left front and right front wheels independently. The BPMV directs fluid to the two rear wheels on a single hydraulic circuit. The BPMV contains the following components.



Pump motor
Three isolation valves
Three dump valves
A front low-pressure accumulator
A rear low-pressure accumulator

Click image to see an enlarged view

Fig. Electronic Brake Control Module (EBCM) (1), Electronic Brake Control Module (EBCM) Electrical Connector - C1 (2), Electronic Brake Control Module (EBCM) Electrical Connector - C2 (3) and left side frame rail (4)



Click image to see an enlarged view

Fig. BPMV hydraulic circuit


BPMV hydraulic circuit components:



(1) Master Cylinder
(2) Master Cylinder Reservoir
(3) Pump
(4) Brake Pressure Modulator Valve (BPMV)
(5) Damper
(6) Rear Isolation Valve
(7) Accumulator
(8) Rear Dump Valve
(9) Right Rear Brake
(10) Left Rear Brake
(11) Left Front Isolation Valve
(12) Left Front Dump Valve
(13) Left Front Brake
(14) Accumulator
(15) Right Front Brake
(16) Right Front Dump Valve
(17) Right Front Isolation Valve
(18) Damper

Wheel Speed Sensors (WSS) - As the front wheels spin, toothed rings located at each wheel hub interrupt magnetic fields in the wheel speed sensors. This causes each wheel speed sensor to generate an AC signal. The EBCM uses these AC signals to calculate the wheel speed. The wheel speed sensors are serviceable only as part of the wheel hub and bearing assemblies. Any imperfections in the toothed ring, such as a missing or damaged tooth, can cause an inaccurate WSS signal.

Vehicle Speed Sensor (VSS) - The input signal for rear wheel speed originates at the VSS. The Powertrain Control Module (PCM) receives rear wheel speed input from the VSS and supplies this information to the EBCM.

Traction control switch (w/NW7) - The TCS is manually disabled or enabled using the traction control switch. The TCS can be programmed to be automatically enabled or disabled when the ignition is turned ON. The factory default is for the TCS to be automatically enabled. Refer to Programming the Traction Control Automatic Engagement Feature.

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Bleeding The Brake System

The brake system must be bled when any brake line is disconnected or there is air in the system.


NOTE
Never bleed a wheel cylinder when a drum is removed.

  1. Clean the master cylinder of excess dirt and remove the cylinder cover and the diaphragm.
  2. Fill the master cylinder to the proper level. Check the fluid level periodically during the bleeding process and replenish it as necessary. Do not allow the master cylinder to run dry, or you will have to start over.
  3. Before opening any of the bleeder screws, you may want to give each one a shot of penetrating solvent. This reduces the possibility of breakage when they are unscrewed.

    Click image to see an enlarged view

    Fig. Connect one end of a clear plastic tube to the bleeder screw and submerge the other end in clean brake fluid



    Click image to see an enlarged view

    Fig. Have an assistant pump, then hold in the brake pedal, while you bleed each wheel

  4. Attach a length of vinyl hose to the bleeder screw of the brake to be bled. Insert the other end of the hose into a clear jar half full of clean brake fluid, so that the end of the hose is beneath the level of fluid. The correct sequence for bleeding is to work from the brake farthest from the master cylinder to the one closest; right rear, left rear, right front, left front.
  5. Depress and release the brake pedal three or four times to exhaust any residual vacuum.
  6. Have an assistant push down on the brake pedal and hold it down. Open the bleeder valve slightly. As the pedal reaches the end of its travel, close the bleeder screw and release the brake pedal. Repeat this process until no air bubbles are visible in the expelled fluid.
    NOTE
    Make sure your assistant presses the brake pedal to the floor slowly. Pressing too fast will cause air bubbles to form in the fluid.

  7. Repeat this procedure at each of the brakes. Remember to check the master cylinder level occasionally. Use only fresh fluid to refill the master cylinder, not the stuff bled from the system.
  8. When the bleeding process is complete, refill the master cylinder, install its cover and diaphragm, and discard the fluid bled from the brake system.

The brake system must be bled when any brake line is disconnected or there is air in the system.


NOTE
Never bleed a wheel cylinder when a drum is removed.

  1. Clean the master cylinder of excess dirt and remove the cylinder cover and the diaphragm.
  2. Fill the master cylinder to the proper level. Check the fluid level periodically during the bleeding process and replenish it as necessary. Do not allow the master cylinder to run dry, or you will have to start over.
  3. Before opening any of the bleeder screws, you may want to give each one a shot of penetrating solvent. This reduces the possibility of breakage when they are unscrewed.

    Click image to see an enlarged view

    Fig. Connect one end of a clear plastic tube to the bleeder screw and submerge the other end in clean brake fluid



    Click image to see an enlarged view

    Fig. Have an assistant pump, then hold in the brake pedal, while you bleed each wheel

  4. Attach a length of vinyl hose to the bleeder screw of the brake to be bled. Insert the other end of the hose into a clear jar half full of clean brake fluid, so that the end of the hose is beneath the level of fluid. The correct sequence for bleeding is to work from the brake farthest from the master cylinder to the one closest; right rear, left rear, right front, left front.
  5. Depress and release the brake pedal three or four times to exhaust any residual vacuum.
  6. Have an assistant push down on the brake pedal and hold it down. Open the bleeder valve slightly. As the pedal reaches the end of its travel, close the bleeder screw and release the brake pedal. Repeat this process until no air bubbles are visible in the expelled fluid.
    NOTE
    Make sure your assistant presses the brake pedal to the floor slowly. Pressing too fast will cause air bubbles to form in the fluid.

  7. Repeat this procedure at each of the brakes. Remember to check the master cylinder level occasionally. Use only fresh fluid to refill the master cylinder, not the stuff bled from the system.
  8. When the bleeding process is complete, refill the master cylinder, install its cover and diaphragm, and discard the fluid bled from the brake system.

cnfg

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