Bench bled master cylinder and bled the brakes pedal still goes to the floor.

2000 GMC SONOMA
108,000 MILES • 4.3L • 6 CYL • 4WD • AUTOMATIC
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BECKYNKEN17
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Changed master cylinder, replaced brake lines. Bench bled master cylinder and bled the brakes pedal still goes to the floor.
Sep 5, 2021 at 4:03 PM
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JACOBANDNICKOLAS
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Hi,

If you bench-bled the new master cylinder and all wheels, chances are air got into the ABS module. What you likely need to do is perform an automated bleed. You will need a scan tool that can perform this procedure.

I attached the directions below. The first part explains to do what you have already done, bleed the brakes. The second part is the automated bleed procedure.

Take a look through this and let me know if you have other questions.

Take care,

Joe

See pic below.
Sep 5, 2021 at 7:57 PM
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BECKYNKEN17
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I already bought two scanners and both said they were capable of doing the auto bleed. I am not going to be buying another one!!! Next!
Sep 5, 2021 at 9:39 PM
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JACOBANDNICKOLAS
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I'm not sure I understand. Are you able to return them?
Sep 6, 2021 at 6:47 PM
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BECKYNKEN17
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The point is I am not doing it with a scan tool. I will find a way to bypass the ABS if that is the case.
Sep 6, 2021 at 7:55 PM
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JACOBANDNICKOLAS
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Hi,

I understand. Let me know if I can help in any way.

Take care,

Joe
Sep 6, 2021 at 9:20 PM