Not so common brake issue.

[Mo Sherif]

2015 chevy tahoe ltz with 22'' 100K.

brake pedal is soft and the car doesn't STOP after driving for a few. hit the brakes and the car rolls to a slow stop.

Replace master, booster, vacuum pump, different pads and rotors now im down to drilled slotted rotors to try and dissipate some of the heat generated.

car stops on a dim when everything is cold but not after 2 or 3 hard stops. i replaced all the fluid and now running dot 5.1 thinking im boiling dot 3 and 4 but still same issue.
all 4 calipers put well over 4000psi of clamping force when cold but can't check it when its hot.
picked up a used abs just to try it but i doubt its gonna be it however im running out of options or things to replace. 

[5proms]

On our '05 Yukon XL, I replaced all the rubber hose caliper lines with stainless steel braided lines at the 180K mile point.  Brought back a nice hard pedal, no more 'ballooning' of the rubber hoses.  It was a kit from Summit Racing.

[Mo Sherif]

 

20 hours ago, 5proms said:

On our '05 Yukon XL, I replaced all the rubber hose caliper lines with stainless steel braided lines at the 180K mile point.  Brought back a nice hard pedal, no more 'ballooning' of the rubber hoses.  It was a kit from Summit Racing.

As much as i agree with you that steel beaded lines will with some spongy pedal feel, they won’t help me. I replaced all the above and bleed over 5 times how the service manual say to bleed the system and i still can’t get the truck to lock the wheels from 10mph. I would like the truck to work as any other Tahoe out there without/before making any kind of upgrade like that. 

[5proms]

Don't know what else to tell you bro', but you have a very challenging problem.

You are right, it should work the right way all the time.

 

Good Luck!

KP