Is it the master cylinder?
Asked by plainshunter Sep 21, 2015 at 07:50 AM about the 2008 Chevrolet Silverado 1500 1LT Extended Cab 4WD
Question type: Maintenance & Repair
Replaced front rotors and brake pads. Went to depress pedal and it went to the floor. Did not come up after pumping. Did not take any lines off, only compressed pistons to accomodate new pads. Pumped brakes, held pedal down and opened bleeder and continue to get air coming out after every pumping. Pedal continues to go to the floor with no resistance felt. .
8 Answers
It sounds as it is the booster, not the mater cylinder...
Rhodes2345 answered 8 years ago
if there is air every time you pump it you have a hole some place. if you pump it up does the peddle get hard at any point? i think one of your brake lines is bad are they wet
plainshunter answered 8 years ago
Could not find any leak anywhere. Have all wheels removed and pulled boots from wheel cylinders and checked pistons. Am curious why you would think it is the booster? Pedal does not get hard at any point at all.
When did you first bleed the brakes? If you bled the brakes after doing the pad change I am thinking you pushed the brake pedal down too far causing damage to the inside of the master cylinder. I always put a piece of wood under the pedal when doing this to keep the pedal off of the floor. Sometimes pushing the pedal farther than it has gone before will damage the cups / seals inside the master cylinder.
Read the manual bleeding paragraph. http://www.linnbenton.edu/auto/brake/bleed.html
http://forum.miata.net/vb/archive/index.php/t-296237.html
plainshunter answered 8 years ago
Changing the master cylinder did the trick. Thanks Bob!
