Brake pedal goes to the floor

BUD BOWLER

MEMBER
2008 CHEVROLET EXPRESS
6.0L
V8
2WD
AUTOMATIC
185,000 MILES

Brakes worked fine, pedal just barely starting to get spongy. Mechanic said master starting to go bad. Tried to replace master cylinder, new one had wrong size fittings. Put old master back on and mechanic bled the brakes. The pedal went to the floor at this point. It did not go to floor before original master cylinder was removed and reinstalled. Still stopped van. Replaced with proper master and bled brakes. Still went to floor. Replaced master second time with another new one, bled brakes, pedal still went to floor. Breaks stop van but go all the way to floor. No air in lines, no leaks anywhere. Any ideas would be great. Thanks

6 Replies

SQM

MECHANIC
6,383 POSTS

Hello,

It is possible to still have air in the brake system as the ABS brake system does have a different process of bleeding. Typical procedure will not work and air will stay trapped and the pedal will go to the floor.

Here is a helpful video:

https://youtu.be/nQRnKyVyMuQ

I have also included the procedures below.

Please let me know of any questions.

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Monday, December 6th, 2021 AT 9:07 PM

BUD BOWLER

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8 POSTS

The work was done by a mechanic shop. I asked them from the beginning if they bled the brakes properly. They said they did. Even when they put my old master cylinder back on is when the problem started. It was never fixed. Even after two new master cylinders.

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Tuesday, December 7th, 2021 AT 11:17 AM

BUD BOWLER

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8 POSTS

Great video. I don't think the shop I used has the electronic tools needed to do this ABS bleed. Thank you. I will get a mechanic that can do this properly.

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Tuesday, December 7th, 2021 AT 11:24 AM

SQM