Bleeding brakes, sucking air from Master cylinder?

[optimusprime]

Just finished my brakes and rotors on my 08 Yukon XL Denali. I bled the back two calipers following the recommended order. Flushed the lines and got all the gunk out until fresh fluid was flowing. No issues with the rear. Filled the MC reservoir each time and kept it full. Then I did my front brakes and rotors. I had to depress the pistons to install the new pads. Boots were in fine condition. Put it all back together and compressed the piston by slowly pressing the brake. Got a good firm feel on my brakes. Began bleeding the front pass side and everything was going fine for about 5 pumps and then it started blasting air. Now I’m at the point where no fluid or very little at most is coming out of the blessed and there is no pedal pressure. MC is full but is making a gasping or sucking sound like a straw at the bottom of a glass when the pedal is released. I can’t figure out what happened. I am using the hose to bleeder with the hose submerged in fluid. There is no air coming in around the bleeder. Please help.


Sent from my iPhone using Tapatalk

 

[Foggy]

You will probably have to activate the AntiLockBrake module...
You will need the proper scanner/device to do that.
Someone else may chime in with some sort of way of getting around
that.... so hang tight

 

[TahoeLT10]

I just did this on my 2010 Tahoe. Rear passenger side, rear driver side, passenger side front, driver side front. Used pressure bleeder. Once finished, used Tech2 to bleed air out, you might want to try the same. Each bleed takes about one full master cylinder to ensure to fill up after each side. I reused Dot3 fluid as it was all coming out clear at this point as I bled everything before getting air out. Pretty much what @Foggy said.

 

[optimusprime]

So I only got to the front pass side and it just started spurting air. It will only gravity drip right now with the bleeder cracked but as soon as pedal pressure is applied it just starts blasting air again with very little fluid. Both front sides have the same effect.


Sent from my iPhone using Tapatalk

 

[Jason in DLH]

Did the MC ever go below the Low Level mark while bleeding? If it did, there is a chance you sucked in air that way.

 

[optimusprime]

What would cause the slurping sound when the pedal is released? No matter how many times I press the pedal with the bleeders closed the pedal won’t firm up any more.


Sent from my iPhone using Tapatalk

 

[optimusprime]

Did the MC ever go below the Low Level mark while bleeding? If it did, there is a chance you sucked in air that way.

Not that I’m aware of. I’m willing to go that route though. What would you suggest I do to chase that rabbit?


Sent from my iPhone using Tapatalk

 

[Jason in DLH]

Or so I’ve heard. A always make sure to keep it at least above the Low Fluid line and have never found out if it can suck in air when it gets lower than that.

 

[George B]

Is it sucking air around one of the reservoir grommets?

 

[Jason in DLH]

I’d probably continue bleeding as normal until no air is present. I’ve never done the method you are using, but have heard that there is a small chance of getting air into the line by doing it that way. I’ve always opted for a vacuum bleeder attached to my little air compressor with no issues.