After replacing both brake lines to rear the brake pedal goes to the floor when starting the car?

2009 BUICK LUCERNE

135,000 MILES • 1.6L • V6 • 2WD • AUTOMATIC

JOE HOIDEN

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It had a leak in a brake line. Replaced both lines to rear. Bled system. I had to replace the master cylinder. Bled lines using vacuum pump. When the car is off, the brake pedal is high and solid. When car is started pedal goes to floor. No visible signs of leaks under the car. When bleeding front drivers' side, had large air bubbles with fluid coming through.

Apr 26, 2024 at 7:21 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 POSTS

Hi,

It sounds like there is air in the ABS system/module. In this case, you need to perform an automated bleed to the system. It requires a bidirectional scan tool.

I attached the directions below for you. Take a look through them and let me know if you are comfortable performing them. Note: In this case, a vacuum pump won't do the job.

Let me know.

Joe

See pics below.

Images (Click to enlarge)

Apr 26, 2024 at 8:45 PM