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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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I replaced the master cylinder and brake booster on a 2012

Customer Question

I replaced the master cylinder and brake booster on a 2012 chevy impala with abs brakes now I cant get a brake pedal manuly bled brake system also performed auto bleed with scanner no signs of air coming coming from bleeders is there something new I'm missing
Submitted: 5 months ago.
Category: Chevy
Expert:  Juan Crespo replied 5 months ago.

Hi there.

The only thing that I can think of is that you might not be using the correct bleeding sequence: You must do Right Rear, then Left Front, then Left Rear, then Right Front. The air will not come out if not bled diagonally and with the auto brake bleed performed with a scan tool.

Here is that procedure in case you need to look it over as reference:

The ABS Automated Bleed Procedure uses a scan tool to cycle the system solenoid valves and run the pump in order to purge any air from the secondary circuits. These circuits are normally closed off, and are only opened during system initialization at vehicle start up and during ABS operation. The automated bleed
procedure opens these secondary circuits and allows any air trapped in these circuits to flow out away from the brake modulator assembly, which is then forced out at the brake corners by the pressure bleeder.

  1. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit
    bleeder valve.
  2. Install a transparent hose over the end of the bleeder valve.
  3. Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11® GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
  4. Repeat above steps for the LEFT FRONT wheel hydraulic circuit bleeder valve.
  5. Loosen the bleeder valve to purge air from the wheel hydraulic circuit. It is important that both bleeder valves be open at the same time. Allow fluid to flow until air bubbles stop flowing from the bleeder, then tighten the bleeder valve.
  6. With the RIGHT REAR and LEFT FRONT wheel hydraulic circuit bleeder valve tightened securely - after all air has been purged from the RIGHT REAR and LEFT FRONT hydraulic circuit - install a proper box-end wrench onto the LEFT REAR and RIGHT FRONT wheel hydraulic circuit bleeder valve.
  7. Install a transparent hose over the end of the bleeder valve, then repeat step 5.
  8. After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
Expert:  Juan Crespo replied 5 months ago.

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