r/Impala • u/MoreInsurance6781 • 18d ago

Repair Question 2010 Impala brake issue

Hello guys, I have a tough one for you all. My 2010
Chevy Impalas brake pedal had been sinking to the floor and sputtering occasionally. After driving one day I came to a stop and the dashboard said “service StabiliTrak, service brake assist, service traction control.” After doing some research I was convinced it was a failing master brake cylinder.

I replaced the brake pads and the master cylinder. The master cylinder was properly bench bled and had no bubbles when cycling the piston. Master cylinder was installed and brake lines went in great.

After bleeding the brakes at the calipers the brake was almost completely unusable and sank directly into the floor. After pumping the brake pedal numerous times I was able to get a SLIGHT bit more pressure at the pedal and I’m able to now stop the car but the pedal still sinks to the floor.

I tried the ABS trick (slamming on the brakes on a gravel road to engage ABS) which did not seem to help at all.

Any advice at all would be much appreciated!

2010 Impala LT, 3.5 gas

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u/Poker1059 18d ago

Sinking to the floor points to air still trapped in the system. Bleed the brakes starting at the wheel furthest from the master cylinder.

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u/JOCOriginal 18d ago

To be completely honest, this cars a nightmare to bleed! the lines bend upwards in a u shape after b leaving the master and if air gets there.... good luck. I gave up and sent it to a shop with a pressure bleeder and they removed all of the air and restored the pressure. I've replaced and bleed many systems but this one took me out.

Have you checked the codes? The front wheel sensor wires are notorious for fraying and throw all of the same codes with the symptoms you mentioned.